Subscriber Login   Users   Administrators
Integrated cloud-based solutions for clinical laboratories

Transfusion Information and Courses from MediaLab, Inc.

These are the MediaLab courses that cover Transfusion and links to relevant pages within the course.

Learn more about laboratory continuing education for medical technologists to earn CE credit for AMT, ASCP, NCA, and state license renewal and recertification. Or get information about laboratory safety and compliance courses that deliver cost-effective OSHA safety training and continuing education to your laboratory's employees.



Alpha Thalassemia
Alpha Thalassemia Intermedia

Alpha thalassemia intermedia (Hemoglobin H Disease) results from a deletion of three out of four alpha chain gene loci. Infants born with alpha thalassemia intermedia appear normal at birth but often develop anemia and splenomegaly by the end of their first year. Development and life expectancy are usually normal, but some affected individuals may require splenectomy and transfusion therapy.Hepatomegaly is not a common finding and there may be some association with mental retardation. Due to the hemolytic nature of this anemia, there may be an increase in respiratory infections, leg ulcers and gallstones. Skeletal changes are not commonly seen in hemoglobin H disease.Any ethnic group can have occurrences of hemoglobin H disease; but it is most often seen in Southeast Asia, the Middle East and the Mediterranean islands.

View Page

Antibody Detection and Identification
Case Study: Immune Alloantibody

A 42-year-old male received 6 units of RBCs during open heart surgery 6 months ago. His antibody screen was negative at that time. He has returned for a follow up surgery and his antibody screen is now positive with both screen cells at the AHG phase.Reactions are occurring at AHG phase, which indicates a possible clinically significant antibody, Jka showing dosage. Refer to Case Study 1 panel below to see reactions of antibody panel.IS = Immediate Spin; AHG = Antihuman Globulin Phase; CC = Check Cells; AC = Auto Control; ND= Not doneCase study 1 conclusion:Patient's previous transfusion 6 months ago exposed him to the Jka antigen, causing the formation of this antibody, which is known for showing dosage.

View Page
References

Alba MA. Clinical Immunohematology Laboratory Manual. Albuquerque, NM: UNM Health Sciences Center; 2008.Brecher MF, Leger RM, Linden JV, Roseff SD, eds. Technical Manual 15th ed. Bethesda, Md. AABB; 2005.Harmening DM. Modern Blood Banking and Transfusion Practices. 5th ed. Philadelphia, Pa: F.A. Davis Company; 2005.

View Page
Naturally Occurring Antibodies

Antibodies are immunoglobulin proteins secreted by B-lymphocytes after stimulation by a specific antigen. The antibody formed binds to the specific antigen in order to mark the antigen for destruction.The type of antigenic exposure occurring in the body determines if the antibody is a naturally occurring or immune antibody.Naturally occurring antibodies can be formed after exposure to environmental agents that are similar to red cell antigens, such as bacteria, dust or pollen. Sensitization through previous transfusions, pregnancy or injections is not necessary. These antibodies are usually IgM and react best at room temperature or lower. Most of these antibodies are not clinically significant with the exception of ABO antibodies. Examples of naturally occurring antibodies include anti-A, anti-B, anti-Cw, anti-M, and antibodies in the Lewis and P system.

View Page
Immune Antibodies

Immune antibodies occur in the serum of individuals who become sensitized to foreign antigens through pregnancy or transfusion. IgM predominates in the primary response, IgG in the secondary response. Most react at 37°C and are considered clinically significant. Examples include antibodies in the Kell, Rh, Duffy, and Kidd systems. Immune antibodies can be classified as alloantibodies or autoantibodies.Alloantibodies Produced by exposure to foreign red cell antigens which are non-self antigens but are of the same species. They react only with allogenic cells. Exposure occurs through pregnancy or transfusion. Examples include anti-K and anti-E. Autoantibodies Produced in an autoimmune process and directed against one's own red cell antigens. React with patient's own cells and all cells tested. Can possibly mask the presence of other significant antibodies. It is very important to make sure that no underlying significant antibodies are present if an autoantibody is suspected. A positive direct antiglobulin test (DAT) or auto control could indicate the presence of an autoantibody. Examples include cold auto (P or I) or warm auto (Rh specificity).

View Page
Example of Clinically Significant Immune Antibody

The panel below shows reactions in the AHG phase only (clinically significant). Pattern reactivity of sample matches the pattern displayed by C on the panel. Anti-C is a clinically significant antibody that can cause both hemolytic disease of the newborn (HDN) and hemolytic transfusion reaction (HTR).ND= not done

View Page
Course Introduction

Antibody screening and antibody identification are critical components in blood bank testing. Clinically significant antibodies must be identified so that appropriate blood products are selected for transfusion and the risk of adverse reaction is minimized. Clinically significant antibodies are capable of causing transfusion reactions, hemolytic disease of the newborn and in severe cases, death.This course will discuss the techniques that are used by blood bank technologists to detect and identify various types of antibodies.

View Page
Significance of Reactions at Different Phases of Testing

Antibodies have optimum temperatures for reactivity. Reaction readings can be made at different phases: after immediate spin, after incubation at 37°C, and after the addition of antihuman globulin (AHG) and centrifugation. Reactivity in a certain phase will help to determine whether the antibody is cold reacting (IgM) or warm reacting (IgG). It will also help to distinguish between antibodies that are clinically significant and not significant. Clinically significant antibodies that are capable of causing acute and delayed hemolytic transfusion reactions (HTR) or hemolytic disease of the newborn (HDN) are usually IgG and react best in the AHG phase.Readings can be done at all three phases if a tube method is used. If a gel method is used, readings are done only at AHG. Immediate spin: Antibodies reacting in this phase tend to be cold reactive. They are usually IgM class and not clinically significant (with the exception of the A and B antibodies). 37°: Antibodies that react in this phase include strong IgM or IgG antibodies. After incubation, the tubes are examined for the presence of hemolysis. If complement was bound during incubation then hemolysis could be seen. NOTE: This reaction would only occur in serum samples. If EDTA plasma samples are used for testing, the complement cascade has been halted. Magnesium and calcium ions are not available for complement to be activated. AHG:Antibodies reacting in this phase are considered clinically significant. They are usually warm reactive and IgG.

View Page

Authentic and Spurious Causes of Thrombocytopenia
References

Beavers C, Kern W, Blick K. Isolated acute thrombocytopenia in a 21-year-old caucasian male. Lab Med. June 2009;40(6):337-339.Bromberg MB. Immune thrombocytopenic purpura, the changing therapeutic landscape. N Engl J Med. 2006; 355:1643-1645. Glassy EF. ed. Color Atlas of Hematology. Northfield, IL: College of American Pathologists; 1998.Kwon JY, Shin JC, Lee JW. Predictor of idiopathic thrombocytopenic purpura in pregnant women presenting with thrombocytopenia. Int J Gynacol Obstet. 2007;85-88. Taghizadeh, M. An update on immune-mediated thrombocytopenia. Lab Med. 2008;39(1):51-54.Tarr PI, Gordon CA, Chandler WE. Shiga like toxin producing Escherichia coli and hemolytic uremic syndrome. Lancet. 2005;365:1073-86.Woelke C , Eichler P. Washington G, etal. Post transfusion purpura in a patient with HPA-1a and GP1a/11a antibodies. Transfus Med 2006;16:69-72. Wyrick-Glatzel J.Thrombotic thrombocytopenic purpura and ADAMTS-13: New insights into pathogenesis, diagnosis and therapy. Lab Med. 2004;35(12):733-737.

View Page
Dilutional Thrombocytopenia

If a patient receives a massive transfusion (usually over 15 units of Red Blood Cells), dilutional thrombocytopenia may result. This thrombocytopenia is transient and the platelet count will usually return to normal once the patient's circulation equilibrates. However, platelet concentrates may need to be administered in the interim.

View Page
Thrombocytopenia in Neonates

Transplacental ITP may occur in newborn infants who are born to mothers with ITP. If the mother has had one baby born with thrombocytopenia, it is usually an indication that all subsequent infants will also be born with thrombocytopenia. A very small percentage of babies born with ITP will have severe thrombocytopenia. Neonatal alloimmune thrombocytopenia (NAIT) is caused by platelet destruction that is the result of alloantibodies stimulated by foreign antigens during pregnancy or blood transfusions. Platelet destruction by alloantibodies may occur in neonates if the mother lacks the platelet-specific antigen but the baby has inherited the antigen from its father. When maternal IgG antiplatelet antibodies cross the placenta, immune destruction of the neonate's platelets occurs. The major concern with both of these conditions is intracranial bleeding if the neonate's platelet count is less than 50 X 109/L. NAIT has a high mortality rate due to bleeding into the central nervous system. Prompt diagnosis of the condition and treatment is critical. The thrombocytopenia lasts on average 3 - 4 weeks postnatal until the maternal antibodies have cleared the newborn's system.

View Page
Treatment of DIC

Transfusion support is given through the use of Red Blood Cells or Fresh Frozen Plasma (FFP) to replace coagulation factors. However, it is crucial that the underlying disorder that caused the DIC be determined and treated. DIC is always a dramatic event and patients may have some lasting complications.

View Page

Basics of Lean and Six Sigma for the Laboratory
Measuring Quality

Laboratory quality indicators are commonly measured as averages or percentages. For example:The turnaround time (TAT) for HIV Western Blot averages 3.5 days.Type O units are available 99.9% of the time in an emergency release.In the first example, it might appears that 3.5 days is a reasonable TAT for a sendout test at first glance, but an average of 3.5 days means the result can be available anytime between the same day to a week later. A patient may have to schedule an appointment at least one week later to ensure the result is available. This may potentially delay treatment. As for the physicians, they want to know when their patients' results will come back; they are not interested in knowing the average but exactly when the result will be available. In the second example, 99.9% might sound impressive but it would translated into 1 out of every 1000 patients requiring emergency transfusion being at risk of ABO hemolytic reaction. In fact if 99.9% is used to measured quality of the processes that happened in our everyday life, that would translate into:18 plane crashes daily17,660 mail mix-ups hourly3,700 medication errors daily10 dropped babies daily$24.8 million worth of incorrect charges hourly500 wrong procedures performed weekly.Other industries realized long ago that measuring quality based on percentage or average is not adequate to satisfy the customers. The need for a higher standard of quality led to the use of Six-Sigma.

View Page
Six Sigma Level of Quality in Health Care

Is there any process in health care that can run at or above Six Sigma level? Transfusion medicine has actually achieved above and beyond Six Sigma, confirming that a Six Sigma level of quality can actually be achieved not only in aviation or manufacturing, but in health care as well. Transfusion medicine is one of the most regulated and earliest adapters of a quality system approach to quality management. Let us look at how transfusion medicine measures up when we translate this statistic into Six Sigma.Based on the FDA Center for Biologics Evaluation and Research (CBER) "Fatalities Reported to FDA Following Blood Collection and Transfusion" annual summary, there were 52 transfusion-related fatalities in the fiscal year of 2007 (October 1, 2006, through September 30, 2007). According to the National Blood Collection and Utilization Survey conducted by AABB, a total of 30,044,000 units of blood components were transfused during 2006. Three opportunities for defect (pre-analytical, analytical and post-analytical) will be used to determine transfusion safety in the United States. By using the formula from the previous page, we can determine both the DPMO and process sigma.DPO = 52/(30,044,000 x 3) = 0.0000005769DPMO = 0.0000005769 x 106 = 0.58Process Sigma = 6.36Transfusion medicine did not achieve Six Sigma level of quality overnight, and other industries who are operating at Six Sigma level, such as the aviation industry, have taken decades to achieve this level of quality.

View Page

Beta Thalassemia
Beta Thalassemia Major

Children with beta thalassemia major, also called Cooley's anemia, usually develop clinical signs during their first year of life. They appear to be malnourished and may exhibit abdominal girth expansion. They show bone marrow expansion and skeletal deformations, which are a result of increased erythropoiesis due to low hemoglobin levels. A common finding is facial bone changes caused by this bone marrow expansion (sometimes referred to as Mongoloid facial features). Other clinical signs include frequent infections, hepatomegaly, splenomegaly, gall stones, leg ulcers, iron toxicity, and poor growth and sexual development. In addition, cardiac failure due to increased burden of the heart attempting to oxygenate the tissues, can lead to serious complications and death if the condition is not treated.In general, death usually occurs by the time these patients are in their early twenties unless treated with blood transfusions along with iron-chelating agents. If no chelating agent is used during treatment life will only be prolonged by about a decade.The different genotypes associated with beta thalassemia major are: B0/B0, B0/B+, or B+/B+.

View Page
Beta Thalassemia Intermedia

Clinically, beta thalassemia intermedia is midway in severity between major and minor. Growth and development in children with this disorder can usually be considered normal and most patients have a normal life span. However, some patients can demonstrate some facial bone deformity and splenomegaly. Hemoglobin levels are usually decreased with a disproportionately high red blood cell count. Transfusions (again with iron-chelating agents) may be used as a supportive therapy if necessary. The genotypes associated with beta thalassmia intermedia are: B+/B+, B0/B+, or B0/B.

View Page

Blood Banking Question Bank - Review Mode (no CE)
The most common cause of severe life threatening hemolytic transfusion reactions is:View Page
Which one of the following is not a benefit of using packed RBCs:View Page
Which of the following is most commonly associated with febrile non-hemolytic transfusion reactions:View Page
Deglycerolized red cells are most effectively used to:View Page
A delayed hemolytic transfusion reaction is most likely to be the result of which of the following antibodies:View Page
Which of the following types of packed RBCs could be transfused to a group O patient:View Page
Which of the following options gives in order from most to least important, the factors you would use to select blood for a transfusion:View Page
An urticarial reaction is characterized by:View Page
The use of the direct antiglobulin test is indicated in all the following except:View Page
After transfusion, a red cell sample from the donor unit, and the recipient's blood sample, must be kept for:View Page
Which of the following conditions is most frequently associated with anti-I:View Page
Which of the following statements best describes Rh antibodies:View Page
Which one of the following statements about directed donations is true:View Page
Autologous blood must be tested for which of the following before transfusion:View Page
Gamma irradiation of cellular blood components is required in which of the following situations:View Page
Antibodies to which of the following are the most frequent cause of febrile transfusion reactions:View Page
How long may blood be stored using CPDA-1 preservative prior to transfusion?View Page
The most severe acute hemolytic transfusions reactions are the result of which of the following:View Page

Chemical Screening of Urine by Reagent Strip (retired March 2012)
Clinical Significance

No blood is found in the urine of healthy individuals although samples from menstruating females, frequently, but not always, test positive for blood. Hematuria is associated with renal or genital urinary disorders in which the bleeding is the result of irritation to the involved organs or trauma. Examples include renal calculi, pyelonephritis, glomerulonephritis, tumors, trauma or exposure to toxic chemicals or drugs and/or strenuous exercise. Hemoglobinuria may be due to the lysis of red cells within the urinary tract. If it is caused by intravascular hemolysis, the hemoglobin is then filtered through the glomeruli. In the normal individual, the hemoglobin molecule attaches to haptoglobin and in this way bypasses the kidney filtration system. When the hemoglobin/haptoglobin system is overwhelmed, as in cases of hemolytic anemia, severe burns, transfusion reaction, infection or strenuous exercise, hemoglobin passes into the urine.

View Page

Chemistry / Urinalysis Question Bank - Review Mode (no CE)
Elevation in conjugated bilirubin is most likely to be found in which of the following conditions:View Page
Increases in LD fractions 4 and 5 are indicative of:View Page

Detecting and Evaluating Coagulation Inhibitors and Factor Deficiencies
Treatment for Factor Deficiencies

Patients who have factor deficiencies may or may not require immediate treatment based upon their risk of bleeding. For example, a patient may only need therapeutic treatment if they are having an invasive surgery or a dental procedure. For the patients who do require treatment, some of the current options are: Transfusion of Fresh Frozen Plasma (FFP) Administration of factor concentrates

View Page

Hemoglobinopathies: Hemoglobin S Disorders
Sequestration Crisis

Sequestration crisis occurs in sickle cell disorders when large numbers of RBCs are suddenly pooled in the spleen and liver. These organs can enlarge rapidly causing pain, hypoxemia, and hypovolemic shock. Treatment of sequestration crisis may include chronic transfusion, exchange transfusion, and/or splenectomy, depending on the patient's age and the severity of the sequestration (as determined by the hemoglobin level and degree of drop in hemoglobin).

View Page
References

Afenyi-Annan, A., Kail, M., Combs, M.R., Orringer, E.P., Ashley-Kock, A., & Telen, M.J. Lack of Duffy antigen expression is associated with organ damage in patients with sickle cell disease. Transfusion. 2008;48:917-924. Ataka, K. I. et. al.Efficacy and safety of the Gardos channel blocker, senicapoc (ICA-17043), in patients with sickle cell anemia. Blood: 2008; 11(8) 3991-3997.Ballas, S.K., Sickle Cell Anaemia: Progress in Pathogenesis and Treatment. Drugs 2002: 62(8); 1143-1172.Bianchi, N., Zuccato, C., Lampronti, I., Borgatti, N., and Gambari, R. Fetal Hemoglobin Inducers from the Natural World: a novel approach for the identification of drugs for the treatment of B-thalassemia and Sickle-cell anemia. eCAM: 2009; 6(2)141-151.Centers for Disease Control and Prevention. Sickle cell disease: Symptoms and treatments. Available at: http://www.cdc.gov/ncbddd/sicklecell/symptoms.html. Accessed January 21, 2010.Harmening, Denise M., Clinical Hematology and Fundementals of Hemostatis 4th., F.A. Davis, 2001.Inati, A., Koussa, S. Taher, A., & Perrine, S. Sickle cell disease: New insights into pathophysiology and treatment. Pediatr Ann. May 2008.Kaushansky, K., Lichtman, M.A., Beulter, E., Kipps, T.J., and Prchal, J.T. Williams Hematology 8th Ed. McGraw Hill 2010.Lotspeich-Steininger, Stiene-Martin and Koepke, Clinical Hematology Principles, Procedures, Correlations, Lippincott 1992. McKenzie, Shirlyn B., Textbook of Hematology 2nd ed., Williams and Wilkins 1996. Miale, John B, Laboratory Medicine Hematology 6th ed., Mosby 1982. Niscola, P., Sorrentino, F., Scaramucci, L., de Faritiis, P., & Cianciulli, P. Pain syndromes in Sickle Cell Disease: An update. American Academy of Pain Medicine. 2009:470-480.Rodak, Bernadette, Diagnostic Hematology, W.B.Saunders Co., 1995.Yoon, S.L. & black, S. Comprehensive, integrative management of pain for patients with Sickle-Cell Disease. Journal of Alternative and Complementary Medicine. 2006: 12; 995-1001.

View Page

Hemolytic Disease of the Fetus and Newborn
Advance Organizer

Before beginning the course take some time to review and think about what you already know about HDFN. For example, jot down brief notes to answer the following questions: Which antibody causes the most severe HDFN? Antibodies in which blood group system are the most common cause of positive direct antiglobulin tests (DATs) in newborns but rarely cause clinically significant hemolysis? Should DATs be performed on all newborns regardless of maternal ABO and Rh blood groups? What is Rh immune globulin (RhIg), its source, constituents, purpose, and mechanism of action? Which tests are used to determine postnatal RhIg dosage? Which type of D variant can produce anti-D? What follow-up tests are typically indicated if a pregnant female has a positive antibody screen when initially tested? Which laboratory findings would suggest that an infant may have ABO HDFN? How can the clinical status of fetuses at risk for HDFN be monitored? What are the characteristics of red cells suitable for intravenous transfusion to fetuses suffering from severe HDFN due to anti-D?

View Page
Introduction

Although HDFN can be life threatening, in the case of anti-D it is a disease that can be prevented. Regardless of causative antibody, HDFN's serious consequences can be lessened by early laboratory diagnosis and treatment. This course begins with an in-depth review of HDFN and later discusses its prevention in detail. In reviewing HDFN, key questions to be answered include: What are the typical signs and symptoms of severe HDFN? Which serologic tests does the transfusion service laboratory use to diagnose HDFN? How is severe HDFN treated? Which development dramatically changed the incidence of HDFN due to anti-D? Other than the causative antibodies, what are some of the main differences between ABO HDFN and HDFN due to anti-D and other antibodies?

View Page
Prenatal Treatment

Prenatal treatment of severe HDFN due to anti-D consists of in utero transfusions. Because of significant risks, transfusion is indicated only if fetal monitoring suggests significant hemolytic disease. 1. Intrauterine Transfusion (IUT)IUTs are done when fetal monitoring indicates severe HDFN and the fetus is too premature for early delivery. IUTs involve the intraperitoneal infusion of packed red cells. The success of the procedure depends on absorption of the red cells through the subdiaphragmatic lymphatic vessels of the fetus. 2. Intravenous transfusion (IVT)Because there may be erratic and inconsistent absorption of intrauterine transfusions in severely hydropic fetuses, IVTs were developed. IVTs involve transfusing donor RBC directly into the umbilical vein.

View Page
Postnatal Treatment: Exchange Transfusion

Whenever possible, a hallmark of HDFN treatment is to induce labor as early as possible once lung maturity has been attained so that the newborn will be able to survive. Once the infant is born, the main treatment for severe HDFN due to anti-D (and other antibodies causing severe disease) is exchange transfusion. In exchange transfusions, up to 85–90% of the infant's blood can be exchanged with donor blood by a process of removing 5–20 mL of blood at a time, and injecting an equivalent amount until the exchange is complete. An exchange transfusion accomplishes the following: Removes bilirubin and thus helps prevent kernicterus; Removes sensitized red cells that have not been broken down yet; Removes circulating maternal antibody; Provides antigen-negative red cells that will not be destroyed by the maternal antibody, thus will survive and provide oxygen to the tissues.

View Page
Other Postnatal Treatment

Besides exchange transfusion, postnatal treatment of HDFN may include the following:RBC TransfusionMany infants who have received IUTs also require simple RBC transfusions in the first few weeks of life to treat ongoing hemolysis caused by persistent maternal antibody in the newborn's circulation.Phototherapy Phototherapy is used to treat jaundice in preterm infants without HDFN and in infants with mild HDFN. Intensive phototherapy has also been used to treat moderate and severe HDFN and decrease the need for exchange transfusion. The newborn is placed under a "blue light" which chemically alters the bilirubin in the surface capillaries to a harmless substance. Human Serum AlbuminHuman serum albumin can also be transfused, either separately or as part of an exchange transfusion in place of FFP. Albumin binds unconjugated bilirubin, thus preventing its deposition in the fat-rich brain cells. Albumin must be used judiciously, because it can aggravate congestive heart failure.

View Page
Fetal Monitoring: Doppler Ultrasonography

Fetal monitoring is used to assess the severity of HDFN and determine whether antenatal transfusion Is warranted.Monitoring can be accomplished by: Doppler ultrasonography Amniocentesis CordocentesisDoppler sonography Doppler sonography is a type of ultrasound that detects and measures blood flow. As related to HDFN, Doppler sonography can be done beginning at 18 weeks. It measures the peak velocity of systolic blood flow in the fetal middle cerebral artery and is used to predict severity of fetal anemia. The hypothesis is that a faster rate of blood flow indicates a more severely anemic fetus, with severe anemia being an indicator of fetal hydrops.Because Doppler sonography is noninvasive and a safer alternative to amniocentesis, it has largely replaced serial amniocentesis for predicting severity of HDFN.

View Page
ABO HDFN - Treatment

Prenatal treatment Prenatal management and treatment of ABO HDFN is not routinely done because: Titers of anti-A and anti-B do not correlate well with severity of disease; The risks of fetal monitoring (e.g., amniocentesis, cordocentesis) and fetal transfusion are greater than the risk of ABO HDFN since it is usually mild and subclinical. However, if a woman has a history of infants with moderate to severe ABO HDFN requiring treatment, she may be monitored so that the infant can be treated for possible HDFN as soon as possible. Postnatal TreatmentTreatment of ABO HDFN usually consists of phototherapy in which the newborn is placed under a "blue light" that chemically alters bilirubin in the surface capillaries to a harmless substance.For more severe cases, exchange transfusion may be performed. Donor RBC for exchange transfusion in cases of ABO HDFN must meet these criteria: Group O; Rh compatible with infant; Less than or equal to 7 days old (or fresher); Reconstituted with AB FFP to obtain a prescribed hematocrit; CMV negative (or equivalent, e.g., leukoreduced by filtration); Negative for hemoglobin S to prevent blood from sickling under conditions of reduced oxygen concentration in the newborn; Irradiated to prevent graft-versus-host disease. Exchange transfusion is also discussed later in the course in the section related to HDFN due to anti-D and other antibodies. Red Blood Cells are crossmatched with maternal plasma, although the infant's plasma can be used if a maternal blood specimen is unavailable.

View Page
All of the following criteria for donor RBC to be used for an exchange transfusion relate to both ABO HDFN and HDFN due to anti-D:Less than or equal to 7 days old (or fresher) Reconstituted with AB FFP CMV negative Negative for hemoglobin S Irradiated View Page
ABO HDFN - Expected Findings

Diagnosis of ABO HDFN is supported by these findings: ABO incompatibility between mother and child, with mother typically group O; Maternal antibody screen negative; Cord DAT weakly positive or negative; Newborn hyperbilirubinemia with jaundice occurring in first 24 hours; Increased spherocytes and reticulocytosis in the newborn; Presence of IgG anti-A or anti-B in cord plasma / serum.

View Page
Factors That Affect Production of Anti-D

Exposure to D+ red cells: Anti-D is red cell immune. The usual route of exposure to the D antigen is during pregnancy. Fetal bleeds into the mother occur more commonly at delivery but some may occur antenatally due to small lesions in the placenta or due to placenta previa, amniocentesis, abdominal trauma, abortion, ectopic pregnancy, etc. Transfusion is a relatively rare route of exposure since Rh-negative individuals normally receive only Rh-negative donor red cells. However, Rh-negative transfusion recipients may be exposed to small volumes of D-positive red cells in Rh-positive platelet concentrates. Also, there are rare reports of fresh frozen plasma, not normally matched for Rh(D), causing anti-D production.Volume of fetal bleed: In general, the larger the fetal bleed, the more likely the mother is to produce anti-D. Approximately 1 pregnancy in 400 result in a fetomaternal hemorrhage (FMH) of 30 mL or greater. ABO incompatibility between mother and fetus: If fetal red cells are ABO incompatible with the mother, maternal anti-A or anti-B will rapidly remove fetal cells from the circulation before anti-D can be produced. This protection decreases the chance of anti-D being produced but does not eliminate it entirely.

View Page
Criteria for Transfused Red Blood Cells

The Red Blood Cells (RBC) that are chosen for exchange transfusion must meet these criteria: ABO-compatible with mother and infant (usually group O) and lack antigens to any maternal IgG antibodies; If mother has anti-D, RBCs are group O Rh negative; No greater than 7 days old; Reconstituted with AB Fresh Frozen Plasma (FFP) to obtain a prescribed hematocrit, e.g., 45–60% (0.45–0.60); CMV negative (or equivalent, e.g., leukoreduced by filtration); Negative for hemoglobin S to prevent blood from hypoxia-induced sickling; Irradiated with a minimum dose of 25 Gray (Gy) to prevent graft-versus-host disease.RBC are normally crossmatched with maternal plasma, although the infant's plasma can be used if a maternal blood specimen is unavailable.

View Page
Molecular Genotyping - Mother

Mother's Rh Type - Weak D or Partial DRecall that some individuals have a variant RHD gene that encodes a reduced concentration of D antigen (weak D) or a D antigen with missing D epitopes (partial D). Various anti-D reagents react differently with these red cells and interpreting Rh(D) type can vary with the method used, e.g., tubes, solid phase, gel. Differentiating between weak D and partial D is important in pregnant women. Those with partial D, but not usually weak D, may make anti-D and should be considered D negative for transfusion and as RhIg candidates. Currently, serologic reagents cannot distinguish the two D variants, but RHD genotyping can.

View Page
Use in Pregnancy

As applied to pregnancy, RhIg's purpose is to prevent immunization to the D antigen in the perinatal period and thus prevent HDFN due to anti-D. If the mother has already produced anti-D, RhIg is of no use in moderating the immune response.Accordingly, RhIg is routinely administered to Rh negative women not previously sensitized to the D antigen under the following circumstances:1, Antenatal. Antepartum prophylaxis of 300 µg (1500 IU) at about 28 weeks gestation in the USA and Canada, which could be weeks later, depending on how appointments are scheduled. To illustrate variation in antenatal international practice, in the UK, smaller doses of RhIg (e.g., 500 IU) may be given at 28 weeks and 34 weeks, although many UK facilities issue a 1500 IU dose at 28–30 weeks. With antenatal administration, the Rh of the fetus is usually unknown. Some transfusion services recommend a further antenatal dose if the infant is undelivered after 40 weeks.2. Postnatal. Prophylaxis of 300 µg (1500 IU) at delivery of an Rh positive or weak D infant within 72 hours of delivery whenever possible. If RhIg administration is delayed beyond 72 hours, laboratory policies differ as to when it would no longer be administered. The longer the delay, the more likely RhIg may fail to suppress production of anti-D, but it is still worth trying. Note: Because RhIg contains IgG anti-D, when given antenatally, it can cross the placenta and sensitize fetal D-positive red cells. Occasionally the fetus may be born with a weakly positive DAT, but significant hemolysis does not occur. For this reason some guidelines recommend that labs do NOT routinely perform DATs on infants whose mothers have received antenatal RhIg.

View Page
RhIg & Variants of D

As noted, policies for administering RhIg to mothers with a variant of D vary among countries and within some countries. An Rh(D) red blood cell phenotype with a weak or variant expression of the D antigen occurs in 0.2% to 1% of whites and is slightly more common in African Americans. The phenotype is routinely called weak D, although several variants exist. A simple model includes these D variants: 1. Weak DMultiple weak D variants exist. Red cells have fewer D antigens/red cell (quantitative difference) and only minor variations in D antigen proteins. Some, but not all, weak D phenotypes are detected by today's Rh typing sera and may be classified as Rh positive or Rh negative by routine testing but will be positive when a weak D test (IAT with anti-D) is done. An extreme form of weak D is the Del phenotype, in which the D antigen is so weakly expressed that it may be demonstrated only by adsorption and elution of anti-D. Weak D individuals do NOT produce anti-D and can be considered to be Rh positive for transfusion and RhIg purposes.2. Partial DPartial D variants have altered Rh(D) proteins that differ sufficiently from normal D antigens (qualitative difference) to allow anti-D production. Partial D red cells may react with some but not all anti-D typing reagents. There are many categories of partial D antigens (e.g., DIIIa, DVI, DAR), each with a unique genetic basis.Some persons with partial D have weakly expressed D epitopes and are designated "partial weak D."In practice, partial D and weak partial D can be considered similarly, i.e., ideally they should be transfused with Rh negative RBC and are candidates to receive perinatal Rh immune globulin depending on the policy in their location.

View Page
RhIg Policies for Weak D

Of the main D variants, a female with partial D (or partial weak D) may develop anti-D to the D epitopes that she lacks. Moreover, partial D red cells adsorb little anti-D, thus leaving enough free RhIg to suppress immunization.However, most laboratories do not routinely differentiate between D variants and instead rely on routine tests and associated test protocols to determine a mother's Rh status for the purposes of RhIg administration. Policies differ between countries and even within countries. 1. Some labs do not test pregnant women for weak D and rely on routine D typing to determine Rh status. AABB Standards for Blood Banks and Transfusion Services, ed. 26 (2010) does not require weak D testing for Rh negative pregnant women, nor for patients requiring transfusion. Note, however, that College of American Pathologists (CAP) surveys have shown that more than 50% of responding laboratories do routinely perform weak D testing on such patients.2. Some labs perform weak D tests on pregnant women who appear to be Rh negative and, if weak D, do NOT inject with RhIg.3. Some labs perform weak D tests on pregnant women who appear to be Rh negative and, if weak D, inject with RhIg based on the possibility that they may be partial D and capable of forming anti-D.

View Page
International RhIg Policies

Currently, policies in the USA and UK favor giving RhIg to women who type as weak D. In Canada, the Society of Obstetrics and Gyneacology recommends not giving RhIg to women who type as weak D BUT in some locations, weak D women do indeed receive RhIg in pregnancy.Many other countries also recommend not giving RhIg to women who type as weak D but policies again vary even within countries.Summary: Because policies vary internationally and change over time AND because the availability of molecular testing to differentiate weak and partial D Rh types will evolve, recommending a specific protocol for RhIg administration and weak D status is difficult. Consult SOPs and policies in your transfusion services manual for the situation in your locale.

View Page
Literature and Online Resources

The following published literature and online resources, while useful, should not be used as a substitute for technical and clinical judgment. Medical and technical information becomes obsolete quickly and current sources relevant to the user's location should always be consulted.References indicated by * provide a broad overview of HDFN and are highly recommended.LITERATUREAvent ND, Reid ME. The Rh blood group system: a review. Blood 2000 Jan 15;95 (2):375-87.Bowman J. Thirty-five years of Rh prophylaxis. Transfusion 2003 Dec;43(12):1661-6.* Eder AF. Update on HDFN: new information on long-standing controversies. Immunohematology 2006;22(4):188–195. (scroll to article)Eder, AF, Manno, C.S. Alloimmune hemolytic disease of the fetus and newborn. In Wintrobe's Clinical Hematology, 11th ed. (Greer JP, Foerster J, Lukens JN, Rodgers GM, Paraskevas F, Glader BE, (eds). Philadelphia, PA: Lippincott, Williams & Wilkins, 2004.Flegel WA. Molecular genetics of RH and its clinical application. Transfus Clin Biol. 2006 Mar-Apr;13(1-2):4-12. Kennedy MS, McNanie J, Waheed A. Detection of anti-D following antepartum injections of Rh immune globulin. Immunohematology 1998;14(4):138-40.Koelewijn JM, de Haas M, Vrijkotte TG, van der Schoot CE, Bonsel GJ. Risk factors for RhD immunisation despite antenatal and postnatal anti-D prophylaxis. BJOG. 2009 Sep;116 (10): 1307-14. Epub 2009 Jun 17.* Kumar S, Regan F. Management of pregnancies with RhD alloimmunisation. BMJ. 2005 May 28;330(7502):1255-8. (UK perspective but much valuable information relevant to all)* Murray NA, Roberts IAG. Haemolytic disease of the newborn. Arch Dis Child Fetal Neonatal Ed 2007 Mar; 92(2): F83–F88. Oepkes D, Seaward PG, Vandenbussche FP, Windrim R, Kingdom J, Beyene J, Kanhai HH, Ohlsson A, Ryan G; DIAMOND Study Group. Doppler ultrasonography versus amniocentesis to predict fetal anemia. N Engl J Med. 2006 Jul 13;355(2):156-64.Ramsey G. Inaccurate doses of Rh immune globulin after Rh-incompatible fetomaternal hemorrhage: survey of laboratory practice. Arch Pathol Lab Med 2009 Mar; 133(3):465-9. Reid ME. The Rh antigen D: a review for clinicians. Blood Bulletin 2008 Apr; 10(1).Sandler SG. Effectiveness of the RhIg dose calculator. Arch Pathol Lab Med 2010 Jul;134(7): 967-8.Shulman IA, Calderon C, Nelson JM, Nakayama R. The routine use of Rh-negative reagent red cells for the identification of anti-D and the detection of non-D red cell antibodies. Transfusion 1994 Aug;34(8):666-70.Tamul KR. Determining fetal-maternal hemorrhage with flow cytometry. Advance 2000. Posted online June 5, 2000.Westhoff CM, Sloan SR. Molecular genotyping in transfusion medicine. Clin Chem 2008;54(12): 1948-50.ONLINE RESOURCESPaxton A. Bringing new rigor to RhIg calculations. CAP TODAY. May 2008. Accessed January 18, 2011.*Wagle S, Deshpande PG. Hemolytic disease of the newborn. eMedicine / WebMD. Updated Apr. 9, 2010. Accessed January 18, 2011.

View Page

Hereditary Hemochromatosis
Initial Treatment

Phlebotomy is considered the treatment of choice for patients with iron overload due to hereditary hemochromatosis (HH). Each unit of blood contains approximately 200 to 250 mg of iron. As erythrocytes are removed by phlebotomy, iron stores are mobilized and utilized in the production of new, circulating erythrocytes. Through periodic phlebotomies, stored iron is removed until iron-deficient erythropoiesis is induced. The initial, or iron reduction, phase of treatment typically consists of removing one unit (450 mL) of whole blood once or twice weekly. Prior to beginning phlebotomy, the patient's hemoglobin and hematocrit must be checked to ensure that the patient is not anemic. A sample for serum ferritin is also collected at this time.Initial treatment goals include inducing iron deficient hematopoiesis without the development of debilitating symptoms of anemia. A hemoglobin concentration of 10.0 to 12.0 g/dL is often used as a target range. The initial treatment phase continues until excess stored iron is removed and ferritin levels decrease to approximately 50 ng/mL. (13) Ferritin and hemoglobin levels are periodically monitored during this phase. The number of phlebotomies needed to reduce iron levels and induce anemia is related to the degree of initial iron overload. Patients may be referred to a hematologist or gastroenterologist during the initial treatment phase. Many patients receive therapeutic phlebotomy services in a hospital or doctor's office, but patients may also undergo phlebotomy at a blood center. Blood collected from persons with HH may be used for transfusion or as blood products if it has been collected from a facility with an approved variance from the US Food and Drug Administration. Not all blood centers have applied for or been granted this variance.(14)The initial treatment phase continues until excess stored iron is removed and ferritin levels decrease to approximately 50 ng/mL. Removal of excess stored iron may take from one month to three years.

View Page

Introduction to Bone Marrow
Increase Marrow Iron Stores

Markely increased stainable iron is present in this biopsy. Iron stores may be increased in sideroblastic anemia, chronic infections, hemochromatosis, hemosiderosis due to numerous blood transfusions, chronic hepatitis, cirrhosis, and uremia.

View Page

Introduction to the ABO Blood Group System
Importance of Understanding the ABO System

The predictability of ABO antibodies appearing in serum lacking the corresponding antigens makes ABO typing a simple process in most cases. However, the importance of getting it right cannot be stressed enough when a patient will be transfused with blood from a donor. If a patient receives donor cells containing A or B antigens and the transfused patient's serum contains the corresponding antibody, the donor cells will be destroyed almost immediately, causing a severe (hemolytic) and sometimes fatal reaction. Therefore, it is of utmost importance to thoroughly understand the ABO blood group system. In addition to red cells, ABO antigenic determinants (epitopes) are found in many tissues, body fluids, and other cells, including endothelial cells and platelets. Because ABO antigens are so widely expressed, ABO antigens are also a major consideration in solid organ and bone marrow transplants.

View Page
ABO Antibodies

In most other blood group systems, antibody may be formed after an individual has been immunized by an antigen that is missing from his or her red cells; perhaps as the result of pregnancy or transfusion. In the ABO system, when the antigen is missing from the cells, the corresponding antibody will predictably be found in the serum and must be found before determining the ABO type. There are few exceptions to this rule and any exception must be explained before the true ABO blood type can be determined.

View Page
Immune ABO Antibodies

A person exposed to a specific immunizing event may produce “immune” ABO antibodies of the same specificity as the naturally occurring antibody, but with different biological behavior. Such immunizing events include pregnancy with an ABO incompatible fetus, or transfusion of ABO incompatible red cells. After immunization, the subject’s antibody may increase in titer and/or avidity, develop powerful hemolyzing properties, or become more active at 37°C.

View Page
Immunoglobulin

The predominant immunoglobulin class for the B antibodies produced by individuals with group A phenotype and the A antibodies produced by individuals with group B phenotype is IgM. Small quantities of IgG and IgA may also be present.The ABO antibodies found in the serum of group O individuals include anti-A and anti-B. An antibody designated anti-A,B is also present. Anti-A,B in group O individuals tends to be predominantly IgG, although IgM and IgA components are also present.Infants of group O mothers are at higher risk for hemolytic disease of the fetus and newborn (HDFN) than those born to mothers with group A or B because IgG immunoglobulins readily cross the placenta. IgM molecules do not cross the placenta because of their larger size. However, the HDFN that results is usually mild and often subclinical. Infants generally survive with little or no intervention.It is important to note that immune antibodies are usually IgG. Both naturally occurring and immune ABO antibodies are critically important in transfusion since both sensitize, and usually hemolyze, red cells with the corresponding antigen.

View Page
Which of the following is NOT a way in which "immune" ABO antibodies may be formed?View Page
Automated Systems

An increasing number of transfusion services are using automated blood banking systems. These systems may employ either solid phase or gel techniques. Use of automation may increase productivity, reduce costs, and, by decreasing the number of manual steps in the testing process, potentially reduce errors.

View Page
Example of an ABO discrepancy

The composite image shown on the right illustrates the ABO typing reactions that were obtained for a patient. This particular case illustrates an ABO discrepancy. An ABO discrepancy occurs when the results of forward and reverse typing do not match. The reactions shown are described below in descending order:Patient red cells with reagent anti-A: negative reaction.Patient red cells with reagent anti-B: 4+ agglutination.Patient red cells with reagent anti-D: 4+ agglutination.Patient serum with reagent A1 red cells: negative reaction.Patient serum with reagent B red cells: negative reaction.This patient forward types as a group B, but reverse types as a group AB. (A group B patient should have anti-A. This patient demonstrates neither anti-A nor anti-B, similar to an AB patient). Further workup is necessary to determine the ABO type since the forward and back typing do not match. In this case, incubation at 40 C demonstrated the presence of weakened anti-A. The patient was therefore typed as group B. This case is an example of an ABO discrepancy which was due to a "missing" anti-A antibody. This could be due to old age, severe illness, or immunosuppression. Although evaluation of ABO discrepancies is beyond the scope of this course, it is important to note that all ABO discrepancies must be resolved before blood products can be released for transfusion.This patient is Rh (D) positive, as evidenced by the strong agglutination of his cells with reagent anti-D antibody.

View Page

Laws and Rules of the Florida Board of Clinical Laboratory Personnel (retired 9/1/2010)
Description of Specialties (2)

Specialists in immunohematology perform all testing prior to blood transfusions and work to prevent transfusion infections. They also investigate any post-transfusion reactions. This specialty includes all lab procedures performed in the specialty of histocompatibility. Specialists in clinical chemistry analyze body fluids such as blood, urine, and spinal fluid to determine the chemical makeup, including the amount of carbohydrates, proteins, enzymes, and trace elements. The special covers urine microscopics and chemical evaluation of the liver, kidneys, lungs, heart, and other vital organ systems. This specialty also covers all testing performed in the specialties of radioassay and blood gas analysis. Specialists in blood banking can perform all immunohematology testing as well as testing from the specialties of clinical chemistry, hematology and serology/immunology that relates to donor blood. Clinical laboratory personnel who are licensed in the specialties of immunohematology, clinical chemistry, hematology, and serology / immunology may perform all tests in the blood banking specialty.

View Page

Medical Error Prevention (retired)
Sentinel Event Categories

Sentinel Events are sentinels--they function as guards or watchkeepers. They indicate serious situations that require immediate attention: Patient deathParalysisComaPermanent loss of functionAny procedure on the wrong patient, the wrong side of the body, or the wrong organ Hemolytic transfusion reaction involving major blood group incompatibility

View Page
The Joint Commission Sentinel Event Alert Since 1998, the Joint Commission has issued 25 Sentinel Event Alerts to the healthcare community. These publications include more than 50 evidence or expert-based recommendations for preventing adverse events. Sentinel Event Alerts address various error reduction topics: Transfusion reactions Inpatient suicide Infant abductions Wrong site surgery or other procedures Patient fallsLaboratory professionals can be involved in all of these types of Sentinel Events. The Joint Commission's first Sentinel Event Alert addressed the common practice of storing concentrated potassium chloride solutions in hospital nursing units. View Page
Types of Medical Errors Medical errors usually belong to one or more of these categories:View Page
Near Misses

Near misses are also related to medical errors: Near misses are medical events that avert unwanted consequences.Someone or something identifies and corrects harmful influences before they cause adverse events.The medical community sometimes calls near misses “close calls.” For example, a transfusion is stopped when the nurse discovers that the identification number on a unit of blood does not match the unit number on the requisition. This is a near miss for the patient receiving a transfusion of incompatible blood. Near misses often provide important insight into new ways of preventing medical errors. In this case, a flaw in Blood Bank cross-checking systems is discovered so it can be prevented from causing a medical error.

View Page
Postanalytic Medical Errors

Errors also occur after analyses are completed and reported. Postanalytic errors begin with the medical professionals who receive test results, and they include interpretation of the results. These errors can occur at--the bedside, chair-side, hospital, clinic-- wherever the patient and the medical professional are located. The possibility for postanalytic medical error continues through diagnosis and treatment procedures and processes. These medical errors occur during the time after the laboratory reports test results. Examples: Wrong test value associated with patient Wrong test interpretation Wrong diagnosis Wrong treatmentLaboratory professionals might believe they are not associated with postanalytic medical errors, but they can be. One deadly example is fatal hemolytic transfusion reaction involving laboratory error.

View Page
Sources of Laboratory-Related ErrorsView Page
These statements describe sources of laboratory-related errors.View Page

Phlebotomy
Discussion

When the results on Mr. John Ready were called to the nurse, she was very surprised that the result of his CBC was normal. The nurse explained to the lab tech that Mr. John Ready had a known diagnosis of lower GI bleeding. His hemoglobin had been very low for the past 24 hours because of the internal bleeding, and she thought it was very surprising that his hemoglobin had normalized so quickly without having received a blood transfusion. Mr. Ready's doctor decided the patient should be redrawn to ensure a correct result. The nurse further questioned if the phlebotomist could possibly have drawn the wrong patient because earlier that day Mr. Ready had been moved to room 831, and room 825 was presently occupied by a patient named Walter Redding. If Julie had checked the patient's armband, she would have realized that the patient in 825 was the wrong patient.Relevant topics:Importance of patient ID, Patient identification continued, Specimen labeling, Specimen labeling Continued, Blood bank specimens

View Page
Concept of Hollister and similar systems

The card has adhesive labels:for blood products,for the blood specimen, anda detachable armband stub,all with identical transfusion numbers.

View Page
Blood bank specimens

Labeling of blood bank specimens is even more critical than labeling of other specimen types.If a patient gets the wrong unit of blood, a serious or even fatal transfusion reaction may occur.

View Page

Red Cell Disorders: Peripheral Blood Clues to Nonneoplastic Conditions
Case Study The image on the right is representative of the peripheral blood smear from a five-month-old immigrant from Asia. Her mother was concerned that the child was not eating well. Her spleen was palpable.These blood count results were reported:ParameterPatient ResultReference IntervalRBC5.5 x 1012/L3.1 - 4.5 x 1012/LHgb9.6 g/dL9.5 - 13.5 g/dLHCT30.4%29- 41%MCV55.4 fl74 - 108 flMCH17.5 pg25 - 35 pgMCHC31.6 g/dL30 - 36 g/dLRDW34.9%11 - 15%Reticulocyte10.9%0.5 - 4.0%Knowing that the family is from a region of Thailand where HbE carriers are prevalent, the physician ordered a hemoglobin electrophoresis. The hemoglobin electrophoresis detected HbE. Based on the blood count results and this representative microscopic field, which of the following peripheral blood findings should be reported?View Page
Hemoglobin E (Hb E) and HbE/Beta Thalassemia

Homozygous Hb E is common in Southeast Asia and presents with very mild anemia and seldom requires transfusion. Over 30 million people in the world are HbE carriers, making this abnormal hemoglobin almost as common as HbS. Hb E is uncommon in North America and in Europe, but with changing immigration patterns, Hb E and related diseases cannot be ignored. Peripheral blood smear findings of target cells, microspherocytes, red cell hypochromia, red blood cell fragments, and nucleated red blood cells may be noted. Evidence from hemoglobin electrophoresis is required to establish a diagnosis.Clinically, a very important and severe disease is Hb E/beta thalassemia in which there is hemolysis requiring repeated transfusions. Severe anemia, low MCV, and elevated RBC are characteristic of Hb E/beta thalassemia.

View Page

Red Cell Morphology
Summary of Anisocytosis

Anisocytosis is a general term reflecting increased variation in the size of red blood cells. The MCV will be within normal limits, but RDW will be increased. Variation usually affects a continuum of red cell sizes, but occasionally two distinct red cell populations can be observed(for example in sideroblastic anemia, or after red cell transfusion.)

View Page

Rh negative female with anti-D at delivery: A case study
Case Presentation

Patient A.D., a 30 year old female, was admitted to the hospital in active labor to deliver at 37 weeks gestation. Transfusion service (TS) records showed A.D. to be group O Rh negative with no record of unexpected red cell antibodies.Maternal history showed two prior pregnancies. Her first pregnancy four years ago ended in spontaneous abortion at 9 weeks gestation and she received a mini-dose (50 µg) of RhIg.In the second pregnancy, two years ago, the infant typed as Group A Rh positive, DAT negative. Patient A.D. was injected with RhIg within 72 hours of delivery. The laboratory also confirmed that in the current pregnancy RhIg was administered at approximately 28 weeks gestation subsequent to a negative antibody screen.After many hours of non-productive labor, the physician considered that labor had stalled and decided to do a cesarian section (C-section). According to hospital policy for C-sections, a type and screen was ordered.

View Page
Introduction

This case concerns a common scenario in the transfusion service (TS) laboratory, the detection of anti-D at delivery in a female who has received Rh immune globulin (RhIg) during pregnancy.Distinguishing between passive and immune anti-D is important clinically: If passive anti-D is misinterpreted as immune, RhIg prophylaxis may be omitted leading to D sensitization. If immune anti-D is misinterpreted as passive, appropriate follow-up of the antibody may be curtailed putting the fetus at risk.Unfortunately, differentiating between immune and passive anti-D is often impossible. This case study presents an opportunity to review perinatal testing programs and the crucial role of RhIg in preventing hemolytic disease of the fetus and newborn (HDFN) due to anti-D. The case also examines practical aspects of routine serologic testing involving neonates and women who have received RhIg during pregnancy. The case is a companion to "Hemolytic Disease of the Fetus and Newborn" and complements its content.In brief, the case will: Guide participants through laboratory findings that need to be interpreted and resolved; Examine current best practices in perinatal testing programs; Review the characteristics of RhIg and its use in pregnancy; Review and investigate key issues associated with detection of anti-D in women who have received antenatal RhIg; Discuss crossmatch and LIS policies related to RhIg-derived passive anti-D.

View Page
Use in Pregnancy

As applied to pregnancy, RhIg's purpose is to prevent immunization to the D antigen in the perinatal period and thus prevent HDFN due to anti-D. If the mother has already produced anti-D, RhIg is of no use.Accordingly, RhIg is routinely administered to Rh negative women* not previously sensitized to the D antigen under the following circumstances:1, Antenatal. Antepartum prophylaxis of 300 µg (1500 IU) at about 28 weeks gestation in the USA and Canada, which could be weeks later, depending on how physician appointments are scheduled. To illustrate variation in antenatal international practice, in the UK smaller doses of RhIg (e.g., 500 IU) may be given at 28 weeks and 34 weeks, although many UK facilities issue a 1500 IU dose at 28–30 weeks. With antenatal administration, the Rh of the fetus is usually unknown. Some transfusion services recommend a further antenatal dose if the infant is undelivered after 40 weeks.2. Postnatal. Prophylaxis of 300 µg (1500 IU) at delivery of an Rh positive or weak D infant, preferably within 72 hours of delivery but can be given up to 28 days later if administration is delayed. If RhIg administration is delayed beyond 72 hours, laboratory policies differ as to when it would no longer be administered.* Policies related to women who are weak D (formerly Du) are discussed later.Note: Because RhIg contains IgG anti-D, when given antenatally, it can cross the placenta and sensitize fetal D-positive red cells. Occasionally the fetus may be born with a weakly positive DAT, but significant hemolysis does not occur.

View Page
RhIg & Variants of D

As noted, policies for administering RhIg to mothers with a variant of D vary among countries and within some countries. An Rh(D) red blood cell phenotype with a weak or variant expression of the D antigen occurs in 0.2% to 1% of whites and is slightly more common in African Americans. The phenotype is routinely called weak D, although several variants exist. A simple model includes these D variants: 1. Weak DMultiple weak D variants exist. Red cells have fewer D antigens/red cell (quantitative difference) and only minor variations in D antigen proteins. Some, but not all, weak D phenotypes are detected by today's Rh typing sera and may be classified as Rh positive or Rh negative by routine testing but will be positive when a weak D test (IAT with anti-D) is done. An extreme form of weak D is the Del phenotype, in which the D antigen is so weakly expressed that it may be demonstrated only by adsorption and elution of anti-D. Weak D individuals do NOT produce anti-D and can be considered to be Rh positive for transfusion and RhIg purposes.2. Partial DPartial D variants have altered Rh(D) proteins that differ sufficiently from normal D antigens (qualitative difference) to allow anti-D production. Partial D red cells may react with some but not all anti-D typing reagents. There are many categories of partial D antigens (e.g., DIIIa, DVI, DAR), each with a unique genetic basis.Some persons with partial D have weakly expressed D epitopes and are designated "partial weak D."In practice, partial D and weak partial D can be considered similarly, i.e., ideally they should be transfused with Rh negative RBC and are candidates to receive perinatal Rh immune globulin depending on the policy in their location.

View Page
RhIg Policies for Weak D

Of the main D variants, a female with partial D (or partial weak D) may develop anti-D to the D epitopes that she lacks. Fortunately, partial D red cells adsorb little anti-D, thus leaving enough free RhIg to suppress immunization.However, most laboratories do not routinely differentiate between D variants and instead rely on routine tests and associated test protocols to determine a mother's Rh status for the purposes of RhIg administration. Policies differ between countries and even within countries. 1. Some labs do not test pregnant women for weak D and rely on routine D typing to determine Rh status. AABB Standards for Blood Banks and Transfusion Services, ed. 26 (2010) does not require weak D testing for Rh negative women.2. Some labs perform weak D tests on pregnant women who appear to be Rh negative and, if weak D, do NOT inject with RhIg.3. Some labs perform weak D tests on pregnant women who appear to be Rh negative and, if weak D, inject with RhIg based on the possibility that they may be partial D and capable of forming anti-D.

View Page
Antibody Exclusion Protocol (General)

Transfusion service (TS) laboratories use different protocols to exclude antibodies. For example:For antibodies whose corresponding antigens exhibit dosage, some laboratories exclude them based on a negative reaction with one homozygous cell.* Other laboratories require negatives with two homozygous cells to increase the confidence that the antibody is not present.If a homozygous cell is not available, some laboratories exclude such antibodies based on a negative reaction with two heterozygous cells.* Other laboratories require negatives with three heterozygous cells to increase confidence that the antibody is not present. * Homozygous and heterozygous do not refer to the red cells per se but to the red cell donors who are homozygous or heterozygous for the genes that determine the red cell phenotypes. See the general antibody exclusion protocol to be used in this case.

View Page
Antibody Titration

Some TS laboratories try to determine if anti-D is passive or immune by performing titrations to determine the titer of the anti-D. Such a protocol usually assumes that an anti-D titer greater than 4 likely represents active immunization. Unfortunately, a titer of 4 or 8 could be active or passive, although a high titer (e.g., 64 or more) almost certainly means the anti-D is immune.Titration results can be affected by several variables: Red cell phenotype; Donor antigen variability (even if the same phenotype); Method used; Operator variability.Because lower titers could be due to both passive and immune anti-D, in the absence of test results that suggest immune anti-D, routine antibody titration is not a good use of time compared to assuming that anti-D is passive. Most transfusion medicine best practice guidelines do NOT recommend routine titration for women known to be injected with RhIg and exhibiting a 2+ or less reaction with D+ red cells, i.e., test results consistent with RhIg-derived passive anti-D.

View Page
Introduction

As noted earlier, in this case study the laboratory's protocol is to set up a mini-panel, providing these criteria are met: Mother is Rh-negative and has been tested on two separate occasions; Laboratory has confirmed administration of RhIg prophylaxis; Result of current antibody screen is positive and typical of anti-D due to RhIg; There is no record or history of an unexpected antibody. All criteria were met and a selected mini-panel was set up to confirm the presence of anti-D and exclude possible co-existing maternal antibodies. Other clinically significant antibodies have implications for possible HDFN and for transfusion to both the mother and newborn, thus must be excluded.

View Page
Crossmatch Issues

In this case the mother did not require transfusion. For reference, the TS laboratory routinely uses an electronic crossmatch to detect ABO incompatibility for cases where patients do not have unexpected clinically significant antibodies in current antibody screen tests nor a history of clinically significant antibodies. When the laboratory information system (LIS) is down, the lab performs an immediate spin crossmatch.Should transfusion have been needed, these questions arise:1. Does a mother with a detectable passive anti-D due to RhIg qualify for an immediate spin (IS) or electronic crossmatch should transfusion be necessary?The issue also extends to the future:2. Should having a record of passive anti-D that is no longer detectable disqualify a woman from being a candidate for an immediate spin or electronic crossmatch?Before proceeding, consider the policies used in your TS laboratory and which rationales are used to support them.

View Page
Crossmatch Implications of RhIg-associated Passive Anti-D

Once again, policies vary from laboratory to laboratory since the issue is not directly addressed by blood safety standards. For example, AABB and other standards require a version of the following: When clinically significant red cell antibodies are detected or the recipient has a history of such antibodies, RBC components shall be prepared for transfusion that lack the corresponding antigen and are serologically crossmatch-compatible, where serologically is taken to be an IAT at 37oC. If no clinically significant antibodies were detected in antibody screen tests and the patient has no record of such antibodies, detection of ABO incompatibility is required, which can be accomplished by immediate spin crossmatch or an electronic crossmatch. The key issues are whether detectable passive anti-D from RhIg or a record of passive anti-D from RhIg should be considered clinically significant for crossmatch purposes. Because standards do not directly address these issues, TS laboratories are left to interpret what is required to meet the standards. Practices may be further complicated because of the transfusion service's laboratory information system (LIS).

View Page
LIS Issues Related to RhIg

Before discussing crossmatch policies for women with passive anti-D likely due to RhIg, LIS-related issues will be outlined. A transfusion service's LIS and how it is configured determines under which circumstances an electronic crossmatch is possible.Regardless of crossmatch policy, almost all laboratories use a special designation or code in their LIS for anti-D likely due to RhIg. Often this designation is entered in the patient history comment field and not the antibody field, thus eliminating the need to remove the passive anti-D from the antibody field when the antibody disappears. Using this policy, once the passive antibody no longer reacts, the patient becomes eligible for an electronic crossmatch without the need to remove the antibody history.In essence, using a special designation for passive anti-D allows the lab to bypass the LIS's normal requirements for patients with clinically significant antibodies, i.e., allows them to omit doing an IAT crossmatch. Examples of how RhIg-derived anti-D is designated in lab information systems: Passive anti-D (eg., code 'PD', 'DPAS', etc.); Probably passive anti-D; Anti-D consistent with RhIg; Anti-D due to RhIg.Depending on the LIS, other variations are possible.

View Page
Literature and Online Resources

The following published literature and online resources, while useful, should not be used as a substitute for technical and clinical judgment. Medical and technical information becomes obsolete quickly and current sources relevant to the user's location should always be consulted.References indicated by * provide a broad overview of HDFN and are highly recommended.LITERATUREAvent ND, Reid ME. The Rh blood group system: a review. Blood. 2000 Jan 15;95 (2):375-87.Bowman J. Thirty-five years of Rh prophylaxis. Transfusion 2003 Dec;43(12):1661-6.* Eder AF. Update on HDFN: new information on long-standing controversies. Immunohematology. 2006;22(4):188–195. (scroll to article).Eder, AF, Manno, C.S. Alloimmune hemolytic disease of the fetus and newborn. In Wintrobe's Clinical Hematology, 11th ed. (Greer JP, Foerster J, Lukens JN, Rodgers GM, Paraskevas F, Glader BE, (eds). Philadelphia, PA: Lippincott, Williams & Wilkins, 2004.Flegel WA. Molecular genetics of RH and its clinical application. Transfus Clin Biol. 2006 Mar-Apr;13(1-2):4-12. Kennedy MS, McNanie J, Waheed A. Detection of anti-D following antepartum injections of Rh immune globulin. Immunohematology 1998;14(4):138-40.Koelewijn JM, de Haas M, Vrijkotte TG, van der Schoot CE, Bonsel GJ. Risk factors for RhD immunisation despite antenatal and postnatal anti-D prophylaxis.BJOG. 2009 Sep;116 (10): 1307-14. Epub 2009 Jun 17.* Kumar S, Regan F. Management of pregnancies with RhD alloimmunisation. BMJ. 2005 May 28;330(7502):1255-8. (UK perspective but much valuable information relevant to all)* Murray NA, Roberts IAG. Haemolytic disease of the newborn. Arch Dis Child Fetal Neonatal Ed 2007 Mar; 92(2): F83–F88. Oepkes D, Seaward PG, Vandenbussche FP, Windrim R, Kingdom J, Beyene J, Kanhai HH, Ohlsson A, Ryan G; DIAMOND Study Group. Doppler ultrasonography versus amniocentesis to predict fetal anemia. N Engl J Med. 2006 Jul 13;355(2):156-64.Ramsey G. Inaccurate doses of Rh immune globulin after Rh-incompatible fetomaternal hemorrhage: survey of laboratory practice.Arch Pathol Lab Med 2009 Mar; 133(3):465-9. Reid ME. The Rh antigen D: a review for clinicians. Blood Bulletin 2008 Apr; 10(1).Sandler SG. Effectiveness of the RhIg dose calculator. Arch Pathol Lab Med 2010 Jul;134(7): 967-8.Shulman IA, Calderon C, Nelson JM, Nakayama R. The routine use of Rh-negative reagent red cells for the identification of anti-D and the detection of non-D red cell antibodies. Transfusion 1994 Aug;34(8):666-70.Tamul KR. Determining fetal-maternal hemorrhage with flow cytometry. Advance 2000. Posted online June 5, 2000.Westhoff CM, Sloan SR. Molecular genotyping in transfusion medicine. Clin Chem 2008;54(12): 1948-50.ONLINE RESOURCESPaxton A. Bringing new rigor to RhIg calculations. CAP Today May 2008. *Wagle S, Deshpande PG. Hemolytic disease of the newborn. eMedicine / WebMD. Updated Apr. 9, 2010.

View Page
ABO, Rh, and Antibody Screen

ABO and Rh typing ABO Forward Group ABO Reverse Group Rh anti-A anti-B A1 cells B cells anti-D* 0 0 4+ 4+ 0 * Transfusion medicine standards used in the hospital's region do not require weak D testing on D-negative pregnant patients and none was done.Antibody screen Cells Gel IAT* Screen Cell I (R1R1) 1+ Screen Cell II (R2R2) 2+ Screen Cell III (rr) 0 * IAT = indirect antiglobulin test

View Page

Risk Management in the Clinical Laboratory
Risk Management Accrediting Organizations: Commission on Laboratory Accreditation

The Commission on Laboratory Accreditation (COLA) was founded in 1988 and in 1993 was granted deeming authority by CMS. Although COLA was initially created to provide voluntary inspections of physicians' offices, COLA now accredits not only laboratories in physicians' offices but also laboratories associated with hospitals, mobile clinics, Veterans Administration, Department of Defense and independent laboratories. Its laboratory accrediting program is also recognized by the Joint Commission. COLA is approved by CMS to accredit the following specialties: Chemistry Hematology Microbiology Immunology Immunohematology/transfusion services Pathology, including cytology, histopathology, and oral pathology

View Page

Routine Venipuncture
Scenario Conclusion

When the results on Mr. John Ready were called to the nurse, she was very surprised that the result of his CBC was normal. The nurse explained to the laboratory technologist that Mr. John Ready had a known diagnosis of lower GI bleeding. His hemoglobin had been very low for the past 24 hours because of the internal bleeding, and she thought it was very surprising that his hemoglobin had normalized so quickly without having received a blood transfusion. Mr. Ready's doctor decided the patient should be redrawn to ensure a correct result. The nurse further questioned if the phlebotomist could possibly have drawn the wrong patient because earlier that day Mr. Ready had been moved to room 831, and room 825 was presently occupied by a patient named Walter Redding. If Julie had properly identified the patient by asking him to state his name and then checking the name and identification number on the wristband, she would have realized that the patient in 825 was the wrong patient.

View Page

The Disappearing Antibody: A Case Study
Case Presentation

Mr. R.M., a 55-year old male, was admitted to a hospital emergency department with severe lower gastrointestinal bleeding. His history revealed multiple prior transfusions, the last of which he received five years earlier.Physical examination revealed hemodynamic instability (systolic BP 60 mmHg). Blood tests revealed a hemoglobin (Hb) of 8 g/dL (80 g/L) and a hematocrit (HCT) of 28% (0.28). The patient received aggressive fluid resuscitation with Ringer's lactate and was sent to the operating room (OR) for an emergency laparotomy.The physician ordered four units of Red Blood Cells to be crossmatched.Two units of uncrossmatched group O Rh-negative Red Blood Cells were also ordered and authorized for immediate emergency transfusion.

View Page
Transfusion Service Laboratory

The transfusion service laboratory (TS) instructed clinical staff to draw blood specimens for compatibility testing before transfusing any blood components or products.Once the blood samples were collected, the clinical staff immediately began transfusing the patient with the O Rh-negative blood.

View Page
Reflecting on probability of the solution

Similar to evaluating inconsistencies, one of the post-analytic tools for confirming that the serological data fit the solution is to consider the "big picture." For example: Is there a likely red cell stimulus (prior transfusion or pregnancy) for IgG antibodies such as anti-Jka? Can different reaction strengths with panel cells be explained by the identified antibody (e.g., dosage) or by the presence of more than one antibody? Is the antibody unusual for a patient of a particular race? For example, anti-Dib is more likely to occur in Native Americans than in Caucasians.

View Page
Antibody identification checklist

To improve the quality of conclusions when identifying antibodies, a checklist is a simple quality control tool to increase transfusion safety. If a specific antibody pattern cannot be identified with acceptable confidence, or if significant serologic or non-serologic data are inconsistent and cannot be rationalized, further testing will be required.Before concluding that the investigation is complete, unless not applicable, mentally reply to each question in the checklist. If any answer is no, has it been resolved? Antibody Identification Checklist Yes/No/NA 1. For a single antibody, does the reaction pattern fit only one antibody specificity? 2. Is antibody specificity consistent with the results of the initial antibody screen? 3. Are reaction phases consistent with antibody specificity? 4. If multiple antibodies are present, can all reactions be explained by the antibody combination? 5. If the autocontrol is negative, are patient red cells negative for the corresponding antigen(s)? 6. Have additional possible antibodies been excluded by selected red cells? 7. Can all variable reaction strengths be explained? 8. If tested, are antigen-negative donor cells compatible by antiglobulin crossmatch? 9. If there are data that do not fit antibody specificity or if there are results that are improbable, are they explainable? 10. Have all results and conclusions been systematically evaluated for consistency?

View Page
As discussed earlier, one of the post-analytic tools for confirming that the serologic data fit the solution is to consider the big picture, as presented below. Think of how you would reply to each question in this case and then click each question to see sample responses.View Page
When performing an antibody investigation, which of the following would indicate an inconsistency that needs to be further investigated? (Select all that apply)View Page
Summary

This case study presents a scenario in which a patient had an unexpected antibody that disappeared after he was transfused with 2 units of unmatched group O Rh negative RBC. The patient developed a positive DAT with MFA but an antibody identification using the post-transfusion red cell eluate was inconclusive, making the antibody unidentifiable. Fortunately, the patient improved and further transfusion was not required. Ultimately, the patient's antibody was identified as anti-Jka, with a second antibody to a low frequency antigen (Radin) also unexpectedly present.The case illustrates the risks involved in using unmatched blood.

View Page
Risks of transfusing unmatched RBC

We often "get away" with transfusing unmatched RBC because the incidence of unexpected antibodies in patients experiencing medical emergencies is thought to be relatively low ( ~3-5% is sometimes cited, but with little solid evidence).Antibody incidence may vary according to several factors: Genetic disposition Patient's underlying disease Number of prior transfusions Gender (females may get exposed to foreign antigens via fetomaternal bleeds as well as transfusion) Concordance of antigen phenotypes of patients vs blood donors in a given locale.In general, antibody incidence increases with the number of transfusions that are given, although most antibody producers will respond within the first 3 - 4 transfusions. Antibody incidence in transfusion-dependent patients, such as those with sickle cell anemia or thalassemia, is very high. Regardless of likelihood, transfusing uncrossmatched blood to a patient with unexpected antibodies can result in a serious hemolytic transfusion reaction.

View Page
Balancing the risks

Life-Threatening HemorrhageDespite potential risk, sometimes immediate transfusion is necessary, even for patients with red cell antibodies. In such cases transfusion service staff should alert the medical director, who can discuss options with clinical staff.The medical director will generally talk to the staff attending the patient and indicate that, if possible, they should hold off transfusion. But if it is a case of massive bleeding where exsanguinating hemorrhage is likely, it is better to give some blood and monitor for a delayed hemolytic transfusion reaction than to let the patient bleed to death.Transfusing when bleeding is brisk will result in much of the autologous and incompatible blood bleeding out, with the possibility of a delayed hemolytic reaction once the patient's antibody rebounds and destroys still present antigen-positive donor red cells.Some transfusion services also try to minimize the risk of unmatched blood by typing their emergency supply of O Rh negative RBCs for the K antigen, since anti-K is a relatively common clinically significant antibody. See Resources for two papers that discuss the risks of transfusing un-crossmatched emergency blood.

View Page
Think about your responses to each of the following questions, then click on the questions.View Page
Literature and online resources

LiteratureDutton RP, Shih D, Edelman BB, Hess J, Scalea TM. [abstract]. Available at: Safety of uncrossmatched type-O red cells for resuscitation from hemorrhagic shock.J Trauma. 2005 Dec;59(6):1445-9. Accessed November 5, 2012.Johnson ST, Rudmann SV,Wilson, SM. Serologic problem solving strategies:a systematic approach. Bethesda, MD: AABB, 1996.Online resourcesThe following are online examples of good practice. The information should not be used as a substitute for technical and clinical judgment. Medical and technical information becomes obsolete quickly and current sources relevant to the user's location should always be consulted.Transfusion reactions: Transfusion complications (Canadian Blood Services)Education website for CBS's hospital customersREACT (Sunnybrook HSC, Toronto, ON, Canada) Pocket reference card for nurseson signs and symptoms of transfusion reactionsQuick cals (online calculator of p values for Fisher's exact test) Use a one-tailed test (since we would expect an antibody to react with red cells that are positive for the corresponding antigen)

View Page
ABO, Rh and antibody screen

These ABO, Rh, and antibody screen results were obtained by the TS using the blood specimen that was collected prior to starting the emergency transfusion with O Rh-negative RBCs. ABO and Rh typing ABO Forward Group ABO Reverse Group Rh anti-A anti-B A1 cells B cells anti-D 0 0 4+ 4+ 3+ Antibody screen Cells Gel IAT* Screen Cell I 3+ Screen Cell II 2+ Screen Cell III 2+ * IAT = indirect antiglobulin test

View Page
The antibody screen is positive but the transfusion of the O Rh-negative RBCs is already in progress. What are the transfusion service (TS) laboratory's priorities in this case?Place the following procedures that will be followed by the TS in the appropriate order of priority.View Page
Crossmatch Results

These are the results of the crossmatch that was being performed in the transfusion service laboratory while the patient was receiving the two units of O Rh-negative RBCs. Cells Gel IAT* Donor I** 2+ Donor 2** 2+ Donor 3 3+ Donor 4 3+ Donor 5 2+ Donor 6 3+ * IAT = indirect antiglobulin test ** O Rh-negative RBC (Donors 3 - 6 are O Rh-positive)

View Page
Which of the following statements about mixed-field agglutination (MFA) are true? Select all that are correct.View Page
Other post-transfusion tests

The patient's post-transfusion plasma was also retested with the 6 RBC that tested positive initially. Like the antibody panel done on the post-transfusion plasma, they are now all negative by gel IAT.Unfortunately, the panel results with the patient's post-transfusion eluate do not give clear results (only cells #1 and #9 react) and the antibody remains unidentifiable. Suppose that the physician had decided to continue transfusing the patient at this stage. Take a moment to think about what you would advise regarding the compatibility of such transfusions, all of which appear to be compatible in the crossmatch. When you have considered the options, continue to the next page.

View Page
Follow-up with clinical staff

The patient's physician was notified that compatible blood was unavailable and that the patient's antibody was still being investigated.When asked whether or not the patient was experiencing a transfusion reaction due to the transfusion of the two unmatched and incompatible O Rh negative RBC, the nurse in the OR stated that the patient was undergoing surgery and completely sedated. A transfusion reaction was not apparent but they would investigate and closely monitor.Hemolytic Transfusion Reactions (HTR)Before proceeding to the next page, make a short list of signs and symptoms associated with immediate hemolytic transfusions reaction and another list associated with delayed hemolytic transfusion reactions.

View Page
Immediate HTR - Signs and symptoms

The following signs and symptoms are associated with acute HTR due to ABO incompatibility but can be associated with other blood group incompatibilities. ABO incompatibility typically results from patient misidentification.The more serious symptoms result from intravascular hemolysis (IVH) caused by antibodies such as anti-A and anti-B that can bind complement to C9.Signs and symptoms typically appear within minutes of the transfusion but can occur anytime during the transfusion. They may include: 1. Burning sensation along the vein being transfused (IVH due to complement activation to C9)*2. Lower back pain in the area of the kidneys (renal failure with subsequent oliguria/anuria) *3. Unexplained bleeding/oozing from a surgical site (fibrinolysis following DIC)*4. Hypotension leading to hypovolemic shock (release of vasoactive substances caused by C3a and C5a)5. Tightness in substernal area of the chest (bronchial constriction due to release of vasoactive substances caused by C3a and C5a fragments)6. Other symptoms: fever, chills, skin flushing, dyspnea, wheezing, anxiety, malaise, nausea, headache. * If untreated, these complications may lead to patient death.

View Page
Delayed HTR - Signs and symptoms

Delayed HTR often go undetected as the symptoms are usually mild and subclinical (death has occurred, but rarely). Symptoms may not occur until days after transfusion when the patient has left the hospital. Donor red cell destruction is usually by extravascular hemolysis (EVH). Signs and symptoms can include: Fever with or without chills Unexplained drop in hemoglobin and hematocrit Transient jaundice due to elevated serum bilirubin

View Page
Signs and symptoms - Job Aids

Some blood safety standards require that a list of common signs and symptoms of suspected adverse reactions be included in both nursing and transfusion service manuals. Several organizations have developed job aids to help clinical staff recognize the signs and symptoms of various suspected transfusion reactions and to suggest appropriate actions (e.g., see REACT in Online Resources).

View Page
Signs and symptoms - Precaution

Signs and symptoms are used only as a general guide to the type of transfusion reaction that may be occurring.Lower back pain, for example, would suggest an acute hemolytic reaction, whereas fever is associated with several types of reactions: Hemolytic (immediate and delayed) Febrile Bacteriogenic

View Page
Which of the following signs and symptoms is most likely to indicate a severe immediate hemolytic transfusion reaction?View Page
Antibody identification (2 weeks post-transfusion)

Fortunately, the patient's condition stabilized and additional transfusions were not required. Two weeks later, new patient specimens were drawn for antibody studies. Antibody identification results Cell Rh Rhesus Kell Duffy Kidd MNSs P Lewis Lu Results Cell C D E c e Cw K k Kpa Fya Fyb Jka Jkb M N S s P1 Lea Leb Lua Gel IAT* 1 rr 0 0 0 + + 0 0 + 0 + 0 + 0 0 + + + +S + 0 0 1+ 1 2 rr 0 0 0 + + 0 0 + 0 + 0 + + 0 + + + +S + 0 0 w+ 2 3 rr 0 0 0 + + 0 0 + 0 + + 0 + 0 + + 0 + 0 + 0 0 3 4 r"r 0 0 + + + 0 0 + 0 + + 0 + 0 + 0 + + + 0 0 0 4 5 R2R2 0 + + + 0 0 + 0 0 + + + + + 0 + 0 + 0 + 0 w+ 5 6 R2R2 0 + + + 0 0 + + 0 + + + + + 0 + 0 + 0 + 0 w+ 6 7 R1R1 + + 0 0 + 0 0 + 0 0 + 0 + + 0 + 0 +S 0 + + 0 7 8 R1R1 + + 0 0 + 0 0 + 0 0 + + 0 + 0 0 + + + 0 0 1+ 8 9 RZR1 + + + - + 0 + + 0 + 0 0 + + 0 0 + + + 0 0 0 9 10 r'r + 0 0 + + 0 0 + 0 + 0 0 + + 0 + 0 +S 0 + 0 0 10 11 Auto 0 11

View Page
When the patient's plasma was non-reactive with panel cells, and very weak and unidentifiable in the post-transfusion RBC eluate, no attempt was made to try to enhance the weak antibodies.We now know that the patient has anti-Jka and that it disappeared rapidly from the patient's plasma after transfusion with two group O Rh-negative RBC. Consider the question below, then click on the question to receive the answer.View Page
Antigen phenotyping

A standard follow-up to antibody identification is to antigen phenotype: Patient's red cells (expecting them to lack the corresponding antigen) Donor red cells (in this case, those transfused before an antibody was identified, or, more typically, to find suitable antigen-negative donors to crossmatch prior to transfusion).If you had wanted to type the patient for any antigens at this point in the investigation (2-weeks post-transfusion), which specimen would you have used? Think about any antigen typing problems and how to overcome them before proceeding to the next page.

View Page
Which of the following statements about antigen phenotyping are true? (Select all that apply)View Page

Transfusion Reactions
Risks of Transfusion

Transfusion of blood components has the potential for both benefit and risk to the patient. According to the FDA Annual Summary of Fiscal Year 2009, 74 fatalities were reported following blood transfusions; forty-four of those fatalities were transfusion-related. Medical errors that could result in transfusion reactions include: Patient misidentification Sample labeling error Wrong blood type issued Transcription error Technical error Storage error Transfusion policies and procedures must be carefully followed to reduce transfusion reactions and prevent transfusion related death or serious injury.Several causes of transfusion-related deaths are summarized in the table below.Reference: U.S Food and Drug Administration. (2009). Fatalities Reported to FDA Following Blood Collection and Transfusion: Annual Summary for Fiscal Year 2009. Retrieved from http://www.fda.gov/downloads/BiologicsBloodVaccines/SafetyAvailability/ReportaProblem/TransfusionDonationFatalities/UCM205620.pdf. Accessed April 26, 2011.

View Page
Categories of Transfusion Reactions

Adverse complications of transfusions can be classified into several categories: Immune-mediated transfusion reactions are those that trigger a response from the patient's immune system. Many transfusion reactions are mediated by the recipient's immune system. These reactions occur as a result of antigen-antibody interactions. Antibodies involved include those with specificity towards antigens on red cells, white cells, or platelets. In general, the immune responses occur in three stages: the immune system detects foreign material (antigen) the immune system processes the antigen the immune system mounts a response to remove the antigen from the body Non-immune mediated hemolytic transfusion reactions are caused by the physical or chemical destruction of transfused RBCs, bacterial contamination, circulatory overload, or citrate toxicity. Acute reactions are those that occur during or within 24 hours after the transfusion. There is usually a rapid onset of symptoms and these reactions may be fatal. Delayed reactions occur weeks or months after the transfusion of blood or blood components.

View Page
Incidence Rates of Transfusion Reactions

The table below lists the incidence rates of several different types of transfusion reactions.Reference: Hillyer, C.D., Silberstein, L.E., Ness, P.M., Anderson, K.C., & Roback, J.R. (2007) Blood Banking and Transfusion Medicine: Basic Principles and Practice 2nd Ed. Philadelphia, PA: Churchill Livingstone.

View Page
In Vivo Red Cell Destruction

Important events that occur in an immune-mediated hemolytic transfusion reaction (HTR) include: Antibody Binding to Red Blood Cells Antibodies may be either IgM or IgG class. IgM antibodies activate complement and lead to intravascular hemolysis where free hemoglobin is released into the plasma. IgG antibodies rarely activate complement but they are often involved in effecting phagocytosis. The concentration of the antibody is directly related to the severity of the HTR. Activation of Complement The end result of complement activation is red cell lysis. Activation of Mononuclear Phagocytes and Cytokines Sensitized red cells are removed from circulation by mononuclear phagocytes. Macrophages in the spleen and Kupffner cells in the liver are active in this process. Activation of Coagulation Antibody-antigen complexes may initiate coagulation and cause disseminated intravascular coagulation (DIC). Shock and Renal Failure Hemolysis can be intravascular or extravascular. In intravascular hemolysis, free hemoglobin, RBC stroma, and intracellular enzymes are released into the blood stream. This results in hemoglobulinemia and hemglobinuria which can lead to kidney damage. In extravascular hemolysis, there is no release of free hemoglobin. Sensitized red cells are removed from the circulation by the monocytes and macrophages in the reticuloendothelial system.

View Page
Iron Overload

A unit of red blood cells (RBCs) contained 250 mg of iron as part of the hemoglobin molecule. A long-term complication of red cell transfusion is iron overload, or hemosiderosis. As red cells are destroyed, they release iron. The iron cannot be excreted and is stored as hemosiderin and ferritin. Iron accumulates in the liver, heart, spleen, and endocrine organs. Tissue damage, heart failure, liver failure, diabetes, and hypothyroidism can occur. Patients who are transfused frequently are at the greatest risk for iron overload. Diseases such as sickle cell disease, thalessemia, aplastic anemia, and other chronic anemias usually require frequent transfusions. Signs and symptoms of hemosiderosis include muscle weakness, fatigue, weight loss, mild jaundice, anemia, and cardiac arrhythmias. Ferritin levels and other iron studies should be assessed. Specific stains may be used to detect iron in tissue biopsies. Iron chelation may be used to treat and prevent iron overload. Chelation works by using an agent which binds to iron and helps remove it through the urine or feces.

View Page
Preliminary Laboratory Investigation

When the laboratory receives notification of a transfusion reaction, the first step is a clerical check. The clerical check should be performed as soon as possible to identify any possible ABO incompatibility. The technologist will compare the component bag, label, paperwork, and patient sample and look for errors. If an error is found, the physician must be notified. Once the post-transfusion sample is received, the sample should be examined for the presence of hemolysis. Both the pre-transfusion sample and post-transfusion sample can be compared. Destruction of red cells and release of free hemoglobin will result in a pink to red supernatant. Pink or red colored serum may indicate intravascular hemolysis. The patient's serum may appear icteric if the hemolytic process is extravascular. The ABO testing must be repeated on the post-transfusion specimen as well. Examination of a post-reaction urine sample made aid in the diagnosis of acute hemolysis. Free hemoglobin in the urine indicates intravascular hemolysis. A direct antiglobulin test (DAT) must be performed on the post-transfusion sample. An EDTA lavender top tube is the required specimen type. If the DAT is positive on the post-transfusion sample, then one should be performed on the pre-transfusion sample. If the pre-transfusion DAT is negative and the post-transfusion is positive, the presence of incompatible red cells should be suspected. All findings must be reported to the supervisor or medical director, who may request additional tests.

View Page
Additional Testing

If preliminary testing suggests hemolysis or if the results are misleading, additional testing may be required. If human error has been ruled out during the clerical check, repeat ABO/Rh testing should be performed on the unit of blood or its segment and the pre-transfusion sample to detect any sample mix ups and clerical errors. Antibody detection studies should be performed on the pre- and post-transfusion samples to look for any unidentified antibodies. If an antibody is identified, the donor cells should be tested for the corresponding antigen. The crossmatch should be repeated with pre-and post-tranfusion specimens using the indirect antiglobulin test (IAT). An incompatible crossmatch with the pre-transfusion sample indicates an original error, either clerical or technical. Incompatibility with only the post-transfusion sample indicates a possible anamnestic response, as in a delayed hemolytic transfusion reaction (DHTR), or sample misidentification. The patient's first voided urine specimen should be examined for the presence of free hemoglobin. The patient's bilirubin levels may also be evaluated. A change from normal pale yellow serum to a post-transfusion bright or deep yellow serum should prompt an investigation for hemolysis. The maximum concentration of bilirubin following hemolysis is not usually detectable until 3 to 6 hours after transfusion. The hemoglobin and hematocrit can be tested to detect a drop in hemoglobin or failure of the hemoglobin to rise after transfusion. Important information about physical or chemical hemolysis may be gained from examining the returned unit bag. If hemolysis is present in the bag or tubing, a process which affected the blood, such as inappropriate warming or faulty infusion pump, should be suspected. If bacterial contamination is suspected, the unit can be cultured. A positive culture indicates a reaction due to bacterial contamination.

View Page
What is the first step a transfusionist should take when a transfusion reaction is suspected?View Page
When performing a transfusion reaction investigation, what is the clerical check used to detect?View Page
Records and Reporting

After the medical director has reviewed the laboratory results from the investigation, the interpretation is recorded on the patient's permanent medical record. The transfusion service must retain the records of the test results, interpretations, and reaction classification indefinitely. In the U.S., deaths of patients resulting from a transfusion reaction must be reported to the Food and Drug Administration (FDA) by the transfusion service as soon as possible. A written report must follow within seven days. The report should contain the patient's medical records, including laboratory reports and autopsy results. Transfusion services accrediting agencies, such as AABB, the College of American Pathologists (CAP), and the Joint Commission may require reporting to them as well. All of these agencies require that transfusion services have written policies for transfusion reactions addressing the steps for detection, evaluation, and reporting.

View Page
Procedure for a Suspected Adverse Reaction

Adverse reactions after transfusion of blood components must be evaluated promptly. Most serious reactions occur within the first 15 minutes of starting a transfusion. Continuous monitoring allows reactions to be discovered in a timely manner. The transfusionist must be able to recognize the symptoms of a transfusion reaction and know the appropriate steps to take when one occurs. The first critical step is to stop the transfusion immediately, but keep the patient's line open with saline. The physician should be contacted immediately for instructions regarding patient care. The transfusion service must be notified of the reaction. They will usually provide instructions on proper documentation of the reaction, and the return of any remaining component and/or tubing. The appropriate patient samples are to be sent to the laboratory and usually include blood and urine. The transfusionist must be sure to follow all hospital policies.

View Page
Transfusion Reactions: Introduction

".....In the past, a person with blood type O negative blood was considered to be a universal donor. It meant his or her blood could be given to anyone, regardless of blood type, without causing a transfusion reaction. This is no longer a relevant concept because of a better understanding of the complex issues of immune reactions related to incompatible donor blood cells." Reference: Mayo Clinic Health Oasis - Ask a Physician 08/09/2000. As quoted in: Blood types and compatibility. Bloodbook.com; 2005. Available at: http://www.bloodbook.com/compat.html. Accessed April 26, 2011.Transfusion of blood components is generally a safe and effective way to correct hematologic deficits. However, a transfusion reaction may occur and health care providers must be aware of the risks involved with blood transfusions and evaluate the risks against the potential therapeutic benefits. A transfusion reaction can be defined as any adverse event occurring during or after the transfusion of blood components. Adverse events can range from fever and hives to renal failure, shock, and death. Some adverse events can be prevented, but others cannot.

View Page
References

Harmening, DM. Modern Blood Banking and Transfusion Practices. 5th ed.Philadelphia, PA: FA Davis; 2005.Hillyer CD, Silberstein LE, Ness PM, Anderson, KC, Roback, JR. Blood Banking and Transfusion Medicine: Basic Principles and Practice. 2nd ed. Philadelphia, PA: Churchill Livingstone; 2007.Roback JD, Combs MR, Grossman BJ, Hillyer CD ed. AABB Technical Manual. 16th ed. Besthesda, MD: AABB; 2008.Rudman, SV. Textbook of Blood Banking and Transfusion Medicine. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2005.U.S. Food and Drug Administration. Blood Products Advisory Committee. April 27, 2007. Available at: http://www.fda.gov/ohrms/dockets/AC/07/briefing/2007-4300B2_01.htm. Accessed December 15, 2010.U.S. Food and Drug Administration. Infectious Disease Tests. 2009. Available at: http://www.fda.gov/BiologicsBloodVaccines/BloodBloodProducts/ApprovedProducts/LicensedProductsBLAs/BloodDonorScreening/InfectiousDisease/default.htm. Accessed December 15, 2010.U.S. Food and Drug Administration. Fatalities Reported to FDA Following Blood Collection and Transfusion: Annual Summary for Fiscal Year 2009. Available at: http://www.fda.gov/downloads/BiologicsBloodVaccines/SafetyAvailability/ReportaProblem/TransfusionDonationFatalities/UCM205620.pdf. Accessed December 15, 2010.

View Page
Causes

Acute hemolytic transfusion reactions (AHTR) are caused when red cells are transfused to a patient with a pre-existing antibody that destroys the transfused incompatible red cells through intravascular or extravascular hemolysis. Life threatening acute hemolytic reactions most commonly occur from the transfusion of ABO incompatible blood. Naturally occurring ABO antibodies bind complement on the red cell surface and have efficient lytic properties which cause intravascular hemolysis. Extravascular hemolysis is characterized by antigen-antibody complexes which do not activate complement. AHTRs feature rapid destruction immediately after transfusion. Rapid hemolysis of as little as 10 mL of incompatible red cells can produce symptoms of an AHTR. Signs and symptoms can occur within minutes after starting the transfusion. Fever is the most initial symptom followed by the chills. These reactions are mostly associated with the transfusion of ABO-incompatible red cells. Causes include clerical errors, such as mislabeled patient samples and mislabeled blood products. Although acute hemolytic reactions are rare with an incidence of 1 to 9 in 100,000 transfusions, they are the most dangerous and are severely life threatening.

View Page
Clinical Laboratory Tests

A post transfusion specimen should be sent to the laboratory for work-up. A clerical check should be performed to investigate possible errors in specimen labeling, blood product issuance, or patient identification. The plasma must be examined for hemolysis. A direct antiglobulin test must be performed. The patient's ABO, Rh and antibody screen should be repeated and confirmed. The blood product ABO/Rh can be confirmed. Other laboratory tests include: complete blood count (CBC), urinalysis, serum bilirubin, creatinine, coagulation profile, and disseminated intravascular coagulation (DIC) evaluation. The full laboratory work-up and details of other laboratory tests will be discussed later in the course.

View Page
Management and Prevention

The first component of therapy is to stop the transfusion immediately. Vital signs must be closely monitored. Management involves treatment of hypotension and disseminated intravascular coagulation (DIC). It is essential to maintain blood volume and adequate renal blood flow. Diuretics, substances that increase urine output, may be administered. If the patient enters renal failure, dialysis must be initiated rapidly. It is impossible to prevent all hemolytic transfusion reactions. The purpose of pre-transfusion compatibility testing is to decrease the probability of a hemolytic transfusion reaction by performing ABO/Rh testing, detecting and identifying alloantibodies, and crossmatching compatible blood. Human error, the most common cause of hemolytic transfusion reactions, cannot be completely eliminated. Steps must be taken to reduce the possibility of human error in identification of patient samples, donor units, and recipients. Each person involved in the transfusion process, from collection of the blood sample to administration of the donor unit, must carefully adhere to each step outlined in the standard operating procedures. All appropriate protocols must be followed. Some examples are: Technologist checks blood sample to ensure proper labeling. Patient's previous transfusion records are examined and all transfusion testing is performed correctly and accurately. Technologist ensures correct unit is released from the blood bank. Transfusionist ensures the recipient is correctly identified.There must be a mechanism in place to train and assess all personnel involved in the transfusion process.

View Page
An acute hemolytic reaction may be caused by which of the following? (Choose all that apply)View Page
Febrile Nonhemolytic Transfusion Reactions: Definition/Manifestation/Prevalence

A febrile non-hemolytic transfusion reactions (FNHTR) is defined as a temperature increase of 1oC over 37oC occurring during or after the transfusion of blood components. FNHTRs are more common in the transfusion of platelets. Multiply-transfused patients and multiparous women make up the largest populations experiencing this type of reaction. There are two mechanisms involved in the manifestation of a FNHTR. The first one involves the presence of a white cell antibody in the patient's plasma that interacts with the white cells in the blood product. These antibodies may be directed against granulocyte antigens or human leukocyte antigens (HLA). This interaction causes endotoxins to be released, which act on the hypothalamus and stimulate a fever. The second mechanism involves the generation of leukocyte cytokines during product storage. The production of cytokines usually occurs during storage in warmer temperatures, which is why non-leukoreduced platelets are commonly implicated.

View Page
Diagnosis, Treatment and Prevention

Diagnosing a febrile non-hemolytic transfusion reaction (FNHTR) involves excluding all other options that may present with fever. If this type of reaction is suspected, the transfusion should be stopped. A transfusion reaction work-up should be initiated, although the antibodies involved with these reactions are not routinely identified because of the difficulty in demonstrating their presence in vitro. Antipyretics, such as acetaminophen, should be administered to the patient and the transfusion can continue once the symptoms subside.A patient with two or more documented febrile nonhemolytic transfusion reactions (FNHTRs) should receive leukocyte-reduced blood components.Pre-storage leukocyte reduction prevents reactions that occur due to cytokine accumulation during storage. Red cell component prevention techniques include the transfusion of fresher blood or washed blood. For platelets, residual plasma may be removed. Antipyretics can be administered prior to transfusion.

View Page
Definition/Manifestations/Prevalence

Allergic reactions are grouped into three categories depending on severity: mild or uncomplicated moderate or anaphylactoid life-threatening or anaphylactic reactionsMild allergic reactions occur in about 1-3% of patients receiving blood products containing plasma. Symptoms are usually mild and include urticaria, erythema (skin redness), and itching. Hives can appear any where on the body and may vary in size. Symptoms usually occur within minutes after the start of the transfusion. They can often last for hours or even days. Mild allergic reactions result from a patient's hypersensitivity to soluble allergens in the plasma of the donor unit. The blood recipient forms antibodies to these allergens that are bound to IgE on mast cells and causes the release of histamines. Allergen substances may be drugs or food consumed by the blood donor. Anaphylactoid and anaphylactic reactions have similar presentations. These reactions are rare but life-threatening. Anaphylactoid and anaphylactic reactions are severe systemic reactions with symptoms such as hypotension, dyspnea, nausea, vomiting, urticaria, and diarrhea. The most life-threatening symptoms include lower airway obstruction, laryngeal edema, cardiac arrhythmia, cardiac arrest, shock, and loss of consciousness. None of these reactions present with fever.

View Page
Diagnosis, Treatment, and Prevention

Diagnosis of allergic reactions is based on the recognition of a skin rash associated with itching. Treatment involves temporarily discontinuing the transfusion and administering an antihistamine. The rash will usually heal when the transfusion is stopped or when an antihistamine is given. Once symptoms have been alleviated, the transfusion may be resumed. If symptoms continue or progress, the transfusion must be stopped and a new donor unit obtained. Premedication will usually prevent urticarial reactions in patients with a history of allergic reactions. If premedication is unsuccessful, washed cellular products may prevent a reaction. Leukoreduction has no role in preventing an allergic reaction. Anaphylatic and anaphylactiod reactions should be recognized when patients develop symptoms described on the previous page. The transfusion must be stopped immediately. Differential diagnosis includes hypotensive reactions, transfusion-related acute lung injury (TRALI), myocaridal infarction, and pulmonary embolus. An IgA deficiency should be investigated and is confirmed by the presence of anti-IgA. Treatment includes timely administration of epinephrine in addition to other supportive care such as vasopressors and airway support. Prevention involves avoiding transfusion of IgA. Cellular products should be washed to remove residual plasma. Products may also be collected from donors who are known to be IgA deficient. Autologous donations are an alternative.

View Page
A febrile nonhemolytic transfusion reaction is characterized by which of the following?View Page
Premedication with antihistamines may prevent an allergic reaction in patients with a history of multiple urticarial transfusion reactions.View Page
Definition and Epidemiology

Transfusion-associated acute lung injury (TRALI) is a complication of blood transfusion that results in shortness of breath due to pulmonary edema, fever, and hypotension. The pulmonary edema is noncardiogenic which means it does not originate from the heart. TRALI is a severely life-threatening adverse reaction. Symptoms manifest within 6 hours of transfusion. Products typically implicated in TRALI are Whole Blood, Red Blood Cells, Fresh Frozen Plasma, Cryoprecipitate, and Platelets, with Fresh Frozen Plasma being the most often implicated product. In combined fiscal years 2005 through 2009, transfusion-related acute lung injury (TRALI) caused the higest number of reported fatalities (48%), followed by hemolytic transfusion reactions (26%) due to non-ABO (16%) and ABO (10%) incompatibilities. Complications of microbial infection, transfusion-associated circulatory overload (TACO), and anaphylactic reactions each accounted for a smaller number of reported fatalities. TRALI has accounted for the highest number of reported transfusion-related fatalities throughout the first decade of 2000.Cases occur in all age groups and genders. Most patients that develop TRALI have no history of adverse reactions. TRALI is generally under-diagnosed and under-reported and the true incidence may be higher than stated estimates. Under-diagnosing is due to lack of recognition of the condition and that it can be easily confused with other diseases. Also, TRALI may be attributed to the underlying condition of the patient.Reference: U.S. Food and Drug Administration Website. Fatalities reported to FDA following blood collection and transfusion: Annual summary for fiscal year 2009. Available at: http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/ReportaProblem/TransfusionDonationFatalities/ucm204763.htm. Accessed April 26, 2011.

View Page
Clinical Presentation and Laboratory Findings

Symptoms begin within 6 hours of transfusion and include acute respiratory distress, severe hypoxemia, hypotension, fever and bilateral fluffy infiltrates on chest radiograph. Respiratory distress is due to noncardiongenic pulmonary edema. Patient may have shortness of breath. Signs and symptoms may be mild, and resolve after a few days, or they may be severe and result in pulmonary failure. Laboratory findings include leukopenia and hypocomplementemia.

View Page
Pathophysiology

The exact mechanism of lung injury in transfusion-related acute lung injury (TRALI) has not be identified. It is believed that the mechanism may vary from patient to patient. The most common finding is leukocyte antibodies in donor or patient plasma. Anitbodies to human leukocyte antigen (HLA) have been associated with TRALI. These anti-HLA antibodies can be formed in response to exposure to foreign antigens from transfusion or pregnancy. The source of the antibody is usually the donor not the patient. Transfused antibodies react with the recipient which results in leukocyte emboli aggregating in the lung capillary bed. Capillary damage triggers interstitial edema and fluid in the alveolar spaces, causing decreased air exchange and hypoxia.

View Page
Diagnosis, Treatment, and Prognosis

There are no conclusive tests to diagnosis transfusion-related acute lung injury (TRALI). The condition should be suspected if the clinical picture corresponds with TRALI clinical findings, such as hypoxemia within 6 hours of transfusion. The clinical findings should correlate with chest radiograph findings of bilateral infiltrates. It is important to rule out cardiac causes of pulmonary edema. One way of differentiating is evaluating the B-type natriuretic peptide (BNP) level, which is known to be elevated in congestive heart failure and not TRALI. In the majority of cases, the donor plasma will demonstrate anti-HLA antibodies. Urgent treatment consists of respiratory and volume support. Patients usually require supplemental oxygen, some by a mechanical ventilator. Vasopressor medications can be used to treat the hypotension. Extracorporeal membrane oxygenation (ECMO) and cardiopulmonary bypass have been successful in treating TRALI when conventional methods do not work. Diuretics are contraindicated in TRALI.Patients with TRALI usually improve within 48 to 96 hours. TRALI is fatal in about 5% to 10% of cases.

View Page
Evaluation of Donors Associated with Transfusion-Related Acute Lung Injury (TRALI)

The AABB published an interim standard in 2005 that states, "Donors implicated in TRALI or associated with multiple events of TRALI shall be evaluated regarding their continued eligibility to donate." A donor is associated with TRALI when one of his/her donor units is transfused 6 hours before the clinical presentation of TRALI in a patient. A donor is implicated in TRALI if he/she is found to have an antibody to an HLA class I or II antigen and the antibody is specific for an antigen on the recipient's leukocytes or a positive crossmatch is obtained.*It is suggested that donors at greatest risk of developing HLA antibodies be tested, such as multiparous women. It has also been suggested that donors that present with demonstrable antibodies and have been implicated in TRALI be permanently deferred from donating. Studies have shown that donors implicated in TRALI reactions may present a future danger to transfusion recipients. Although, there are some instances where donors with HLA antibodies have not caused TRALI reactions. Another option would be to wash all red cell products from these donors in special circumstances such as rare donors. Reference: Association bulletin #05-09. AABB; August 2005. Available at: http://www.aabb.org/resources/publications/bulletins/Pages/ab05-09.aspx. Accessed November 12, 2010.

View Page
Prevention of Transfusion-Related Acute Lung Injury (TRALI)

The AABB has made several recommendations for preventing TRALI including: Blood collection facilities should implement interventions to minimize the preparation of high-plasma-volume components from donors known to be leukocyte-alloimmunized or at increased risk for leukocyte alloimmunization. Blood transfusion facilities should work toward implementing appropriate evidence-based hemotherapy practices to minimize unnecessary transfusion. Blood collection and transfusion facilities should monitor the incidence of reported TRALI and TRALI-related mortality. Transfusion services should work with clinicians to educate providers about the risks of TRALI and about the need to work toward implementing evidence-based transfusion practices for all blood components, with special emphasis on high plasma-volume components. High-plasma-volume components include the following: FFP obtained from whole blood or apheresis Plasma frozen within 24 hours Cryoprecipitate-reduced plasma Apheresis platelets Whole bloodThere have been several other suggestions for preventing TRALI, which include: Screening of all donors for anti-neutrophil or anti-HLA antibodies. Once donors are identified, they are excluded from donating, or their blood is used for products that do not contain much plasma. This method would not prevent TRALI in recipients who have alloantibodies. Use of pre-storage leukoreduced blood. Use of younger blood products. Appropriate utilization of blood products. Using blood products only when clinically indicated may reduce the frequency of TRALI. Because TRALI can coexist with other transfusion reactions and with pulmonary complications unrelated to transfusion, the diagnosis of TRALI is difficult, but it is an important step in monitoring the effectiveness of TRALI risk-reduction strategies.

View Page
Presentation and Prevalence

Although the risk of acquiring transfusion transmitted viral infections is low due to donor testing, bacterial infections are still reported. Platelets are the most implicated product in bacterial contamination reports because they are stored at room temperature (20-24oC) and provide a favorable environment for bacterial growth. Sespis occurs in about 1 in 25,000 platelet transfusions. It may be fatal in about 1 in 60,000 transfusions. Bacteria can be present in other components as well, such as red blood cells (RBCs), cryoprecipitate, and plasma. Contamination in red cell components is rare with events occurring 1 in 250,000 transfusions. This low incidence is due to the refrigerated storage requirements for red cells at 1-6oC. Because plasma and cryoprecipitate are stored frozen, they are least likey to contain bacteria. Contamination usually occurs when these products are thawed in a water bath that contains bacteria. Reactions range from minimal or no symptoms to fatal septic shock and death. Severity of the reaction depends on the bacterial species involved, the concentration and growth rate of the organisms, and the recipient's immune status. Septic reactions can present with a fever of higher than 38.5oC, rigors, and hypotension that begin during the transfusion. Patients may also have nausea, vomiting, dyspnea, and diarrhea. Septic shock, oliguria, and disseminated intravascular coagulation (DIC) are also complications.

View Page
Bacteria Implicated in Contamination

Yersina entercolitica is most likely responsible for septic reactions in transfusions of Red Blood Cells. This organism is usually acquired by ingestion of contaminated food and causes mild symptoms of abdominal pain and diarrhea. Growth of Y. entercolitica is enhanced in iron-rich environments such as red blood cells. Other organisms reportedly found in Red Blood Cell units are Campylobacter species, Serratia species, Pseudomonas species, Enterobacter species, and Echerichia coli. These bacteria can produce endotoxins which cause a reaction in the patient. The majority of organisms associated with platelets transfusions are normal skin flora. Staphylococcus aureus, coagulase-negative staphylocci, aerobic and anerobic diptheroid bacilli, streptococci, and gram-positive bacilli are frequently isolated. Some transfused organisms have been implicated in a delayed post-transfusion illness. Pseudomonas aeruginosa and Burkholderia capacia have been isolated in cryoprecipitate and plasma. These organisms grow optimally at 30oC and have been found in water baths, accentuating the importance of overwrapping components that are thawed in a water bath. Rickettsia organisms are intracellular bacteria which are transmitted by ticks or insects. These bacteria are the causes of Rocky Mountain spotted fever, ehrlichiosis, and scrub typhus, and may be transmitted by transfusion. Similarly, the organism which causes Lyme disease may be transmitted as well. There have no reports of either of these organisms transmitted by transfusion.

View Page
Reducing Transfusion-Associated Septic Reactions

Measures taken to reduce bacterial contamination of blood components include donor screening, improved skin disinfection, diversion of the first aliquot of blood, and pretransfusion bacterial detection. Screening of donors is done by questioning them about fever occurrence and dental or medical procedures that occurred days before donation. Donors who develop symptoms of an infection may be asked to notify the blood bank. Complete skin disinfection is not possible because of organisms living in places that are inaccessible, such as sebaceous glands and hair follicles. Factors affecting skin disinfection are the type and concentration of antiseptic, use or single or multiple antiseptics, method and steps of application, and contact time. Studies have shown that a two-stage method using a sponge scrub and ampule with tincture of iodine is the most effective method. The AABB recommends an initial 30 second scrub with a 0.7% iodophor solution followed by the application of a 10% iodophor compound, which must be allowed to dry for 30 seconds. To avoid normal flora contamination, blood may be diverted into a satellite bag at the beginning of donation. These bags are developed so that backflow is prevented. Blood contained in the satellite bag is used for blood grouping and infectious disease testing. Blood diversion is not a mandatory practice in the United States. The AABB requires that the transfusion service have a method to detect bacteria in all platelet components. Culture-based methods are used at blood collecting facilities near the time of collection. Hospital-based transfusion services use other less costly non-culture based methods such as gram staining or pH and glucose analysis prior to releasing the product for transfusion. Recently, a qualitative immunoassay for the detection of bacteria in platelets has been developed. This test detects antigens on the cell walls of the bacteria. It has been documented to be more sensitive than other non-culture based methods.

View Page
Transfusion-Associated Circulatory Overload (TACO)

Transfusion-associated circulatory overload (TACO) is caused by the inability of the circulatory system to handle an increased blood volume. This usually occurs if the product is infused into the patient too quickly. The very young, elderly, patients with small stature, and patients with compromised cardiac function are at heightened risk for circulatory overload. The frequency is difficult to determine since many instances go unreported. The patient will present with acute pulmonary edema when cardiac output cannot be maintained. Other symptoms include, cyanosis , orthopnea, hypertension, headache, tachycardia, chest tightness, and cough. Symptoms set in near the end of the transfusion or within six hours of completion. Symptoms may be confused with transfusion-related acute lung injury (TRALI). Recently, B-type natriuretic peptide (BNP), a cardiac marker, has been used as a diagnostic tool. BNP is elevated with TACO.The transfusion should be stopped as soon as TACO is suspected. The patient should be in a sitting position and provided with supplementary oxygen. Intravascular volume may be reduced by the administering of diuretics. Blood components should be adminstered slowly when possible, particularly in patients at risk for TACO.

View Page
Physical and Chemical Mechanisms of Hemolysis

Patients can experience a transfusion reaction caused by a range of physical or chemical factors. These factors can either affect the blood component or result from a transfusion event. These reactions include physical red cell damage, depletion or dilution of coagulation factors and platelets, hypothermia, citrate toxicity, hypokalemia or hyperkalemia, and air embolism. Membrane damage and lysis can occur to red blood cells (RBCs) because of hypotonic or hypertonic solutions, heat damage from blood warmers, and mechanical damage caused by blood pumps. Platelets and coagulation factors may become depleted or diluted from a massive transfusion. Hypothermia, a core body temperature of less than 35oC, can occur from transfusions of large volumes of cold products. Hyperkalemia is caused by the intracellular loss of potassium from the red cells during storage. Hypokalemia may result from transfusion of potassium depleted cells such as washed RBCs. Signs and symptoms of physically or chemically induced reactions are non-specific. Some of the more common signs include: Chills Numbness Nausea Vomiting Cardiac arrhythmias Altered respirations Additional laboratory tests to investigate a reaction are electrolytes, blood pH, glucose, urinalysis, complete blood count (CBC), prothrombin time (PT) and activated partial thromboplastin time (aPTT). Treatment involves correcting the underlying cause of the symptoms. For example, a patient with hypothermia may be given a heat blanket. Attention to proper transfusion practices will help prevent these types of reactions.

View Page
Definition and Incidence

Delayed hemolytic transfusion reactions (DHTR) are reactions that occurs 3 to 10 days after the transfusion. Usually, the blood appears serologically compatible at initial testing. Delayed reactions are common in patients who have been immunized to a foreign antigen from a previous transfusion or pregnancy, but the antibody titers decrease over time and the antibody is not detectable during pre-transfusion testing. The transfusion leads to a secondary (anamnestic) response, causing increased antibody production that sensitizes antigen-positive donor red cells. Hemolysis is extravascular. Sensitized cells are removed from circulation by the reticuloendothelial system, also called the monocyte-macrophage system. Because there is a delay in the presentation of symptoms, DHTR is not usually considered as a cause of the clinical presentation. The transfusion service usually initiates investigation of a DHTR because of serologic findings in a post-transfusion specimen. DHTRs occur more frequently than acute hemolytic reactions. Approximately 1:2500 transfusions result in a DHTR.

View Page
Diagnosis

The symptom most commonly associated with a delayed hemolytic transfusion reaction (DHTR) is unexplained decrease in hemoglobin and hematocrit. Patients may also present with fever and jaundice. Hemolysis occurs slowly and is primarily extravascular. Unlike an acute hemolytic transfusion reaction (AHTR), hemoglobinuria, acute renal failure, and disseminated intravascular coagulation (DIC) are not generally seen. On some occasions, patient's may not present with any symptoms. Serologic findings include a positive direct antiglobulin test (DAT) and/or a positive antibody screen in post-transfusion testing. In many cases, the physician will send a request for an additional transfusion because of the decreased hemoglobin levels, and not suspect a DHTR. The positive antibody screen will trigger an investigation including antibody identification. The DAT may have a mixed field appearance because of the antibody-sensitized transfused red cells and the non-sensitized patient red cells. Segments from the donor unit can be tested for the offending antigen once the antibody has been identified.Antibodies that are most often reported as the cause of DHTR are anti-Jka and anti- Jkb. Other antibodies that are also commonly implicated in a DHTR include Kell, Rh, and Duffy system antibodies.The patient's physician should be notified so that additional clinical and laboratory evidence can be evaluated.

View Page
Severe Delayed Hemolytic Transfusion Reactions (DHTR)

Generally, the clinical symptoms of a delayed hemolytic transfusion reaction (DHTR) resolve within 2-3 weeks without medical intervention other than transfusion support. On the other hand, severe DHTRs can occur with a life-threatening anemia. Severe delayed reactions occur most often in patients with sickle cell anemia. Sickle cell anemia patients have a high alloimmunization rate which puts them at greater risk for developing a DHTR. Diagnosis of a DHTR can be difficult in sickle cell patients because symptoms can be misdiagnosed as sickle cell crisis pain. Delays in medical treatment may lead to death. It is important for the transfusion service to obtain an accurate transfusion history. It is unclear what causes such severe reactions in sickle cell patients. Several explanations include bystander hemolysis, sickle cell hemolytic transfusion syndrome, and hyperhemolysis. In any case, it is important to recognize that severe DHTR in sickle cell patients is not uncommon. Treatment requires rapid diagnosis and transfusion support with antigen-negative red cells.

View Page
Prevention

The most critical aspect of prevention is for the transfusion service to document all clinically significant antibodies. One challenge in antibody detection is finding a rapid method that is sensitive enough to detect low titers of clinically significant antibodies without being too sensitive for insignificant antibodies. Preventing severe reactions in sickle patients can be done by phenotyping the patients. This is useful in providing phenotypically matched blood and solving complex antibody identification problems.

View Page
Delayed hemolytic transfusion reactions (DHTR) typically occur 3 hours after transfusion.View Page
Definition and Incidence

Transfusion-associated graft versus host disease (TA-GVHD) is a rare but highly lethal adverse reaction. The disease has a 90% mortality rate. It is caused by the transfusion of donor lymphocytes to a recipient who is immunocompromised. The donor lymphocytes engraft and escalate an immune response against the host's tissues including organs such as the lungs, skin, intestines, and liver. The recipient is unable to destroy the foreign lymphocytes and the cells proliferate and respond to incompatible antigens in the host. Certain recipients have increased risk for developing TA-GVHD. They are: Neonates less than 4 months of age Fetuses Recipients with a congenital or acquired immunodeficiency Recipients of donor units from a blood relative

View Page
Clinical Presentation and Diagnosis

Patients present with fever, a characteristic red rash from trunk or face to the extremities, watery diarrhea, nausea, vomiting, and hepatitis within seven to ten days following the transfusion. The rash may progress to blister-like lesions and erythroderma. Pancytopenia will develop due to the immune destruction of the recipient's bone marrow. The low platelet count causes hemorrhaging while a low white blood cell count can lead to infection. Most patients die within one to three weeks after the onset of symptoms. The diagnosis is often missed and is usually made too late or after death. Routine laboratory studies are not helpful. The only definitive method is the identification of donor lymphocytes in the circulation or tissues of the recipient which is accomplished through human leukocyte angtien (HLA) typing or cytogenic analysis.

View Page
Definition/Manifestation/Prevalence

Post-transfusion purpura (PTP) is a very rare complication of blood transfusion. It has been most commonly associated with the transfusion of red blood cells (RBCs) and whole blood, but has also been seen in platelet and plasma transfusions. It is characterized by a rapid onset of thrombocytopenia, or decreased platelet count, which results from the product of a platelet alloantibody. Platelet counts are usually less than 10,000/uL. Reactions occur around 7 to 14 days post-transfusion. Patients present with purpura, bleeding from the mucous membranes, gastrointesinal ,and/or urinary tract bleeding. Melena and vaginal bleeding have also been reported. The thrombocytopenia is usually self-limiting. Platelet counts and coagulation studies aid in the diagnosis. Patients can also be tested for platelet specific antibodies, human leukocyte antigen (HLA) antibodies and lymphocytotoxic antibodies. The differential diagnosis includes other causes of thrombocytopenia.

View Page
Pathophysiology, Treatment and Prevention

Post-transfusion purpura (PTP) is caused by platelet-specific antibodies in a patient who has been previously exposed to platelet antigens through pregnancy or transfusion. The most frequently identified antibody is Anti-PLA1 which reacts with platelet antigen HPA-1a. The platelet antibody binds to the platelet surface which allows for extravascular removal through the liver or the spleen. The patient's own platelets are destroyed as well, thus aggravating the thrombocytopenia. Three theories are suggested regarding the destruction of autologous platelets. One suggests that immune complexes bind to the platelets through the Fc receptor and cause destruction. The second theory proposes that the patient's platelets absorb a soluable platelet antigen from the donor plasma. The third hypothesis, which has the most support, states that the platelet alloantibody has autoreactivity that develops when the patient is exposed to the foreign platelet antigen. Platelet transfusion is NOT a treatment option. Steroids, whole blood exchange, and plasma exchange are accepted options for treatment. According to the AABB, intravenous IgG (IVIG) is the treatment of choice (AABB Technical Manual, p. 744). Most patients will respond to treatment within several hours to four days. PTP does not usually re-occur but it is recommended that patient's with a previous reaction be transfused with antigen-matched components. Autologous donations or directed donations from antigen matched family members may be the best sources of blood. PTP has been known to occurr even after the transfusion of deglycerolized rejuvenated or washed red cells, so these processes do not prevent a reaction.

View Page
Post-transfusion purpura (PTP) is characterized by which of the following?View Page


MediaLab, Inc.

http://www.MediaLabInc.net    |    (877) 776-8460 (tollfree)    |    sales@medialabinc.net