| Summary The normal RBC count (4.84 x 1012/L) in this case, together with the decreased hemoglobin (8.4 g/dL) and MCV (59 fl) is an indicator of ineffective erythropoeisis that often points to thalassemia.The RBC morphology shows slight hypochromic microcytosis with codocytes, schizocytes, and basophilic stippling. Schizocytes form by several mechanisms, one being the removal of RBC inclusions.This patient's elevated bilirubin correlates with her presentation of sclera icterus; her splenomegaly is consistent with increased RBC destruction.The Hb electrophoresis demonstrated a normal pattern, initially, but the unstable Hemoglobin H was revealed upon repeat electrophoresis with reduced incubation time. Hemoglobin H is the result of beta globin chain tetramer formation due to the insufficient supply of alpha globin chains in alpha thalassemia intermedia.People with Hemoglobin H disease (alpha thalassemia intermedia) usually have a normal life expectancy without treatment. However, hemolysis may lead to moderate anemia that may be treated with splenectomy. | View Page |
| Serum Bilirubin Bilirubin is formed as a result of hemoglobin degradation. Normally, senescent red blood cells are removed from circulation and the bilirubin that is formed is processed by the liver. The normal level of bilirubin in the serum of adults is 0.2-1mg/dl. Bilirubin levels increase with liver disorders and also in anemia that is a result of a hemolytic process. Patients may display jaundice when serum bilirubin levels exceed 2mg/dl.Persons with alpha thalassemia intermedia usually have an increased bilirubin level, because of ongoing hemolysis. This bilirubin is typically the unconjugated fraction of bilirubin. | View Page |
| Lactate Dehydrogenase Lactate dehydrogenase is found in the cytoplasm of every cell. LD is present in the serum at a level of 100-190 U/L. The serum LD level will rise during increased cell damage.Persons with alpha thalassemia intermedia usually have an increased levels of lactate dehydrogenase (LD). This LD is of red blood cell origin, which leaks in to the plasma during hemolysis. | View Page |
| Serum Haptoglobin Haptoglobin is the plasma protein responsible for binding free hemoglobin during episodes of hemolysis and would normally demonstrate decreased levels during a hemolytic crisis.The normal level of haptoglobin is 40-330mg/dl. Individuals who are in hemolytic crisis demonstrate greatly reduced levels to an absence of haptoglobin.In alpha thalassemia, however, haptoglobin levels remain normal or only slightly decreased, even during hemolytic events.The reason for this is that haptoglobin functions by binding the alpha chain portion of hemoglobin. With the absence of these chains in alpha thalassemia major and intermedia, haptoglobin cannot bind free hemoglobin. Therefore it is not consumed. | View Page |
| False Negative Results False negative results may occur with some methods when the concentration of ascorbic acid is greater than 5 mg/dL. The sensitivity of the blood portion of the test strip is decreased in specimens with a high specific gravity and increased protein. High levels of nitrites may delay the reaction, causing a false negative to be reported. If the pH of a urine sample is below 5, hemolysis of red cells as part of the test reaction is inhibited which results in a false negative reaction. An improperly mixed specimen may test negative if the red blood cells are in the sediment. | View Page |
| 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 |
| Clinical Significance Urinary urobilinogen may be increased in the presence of a hemolytic process such as hemolytic anemia. It may also be increased with infectious hepatitis, or with cirrhosis. Comparing the urinary bilirubin result with the urobilinogen result may assist in distinguishing between red cell hemolysis, hepatic disease, and biliary obstruction. Urobilinogen is increased in hemolytic disease and urine bilirubin is negative. Urobilinogen is increased in hepatic disease, and urine bilirubin may be positive or negative. Urobilinogen is low with biliary obstruction, and urine bilirubin is positive. Reagent strips methods however, cannot distinguish normal urobilinogen from absent urobilinogen, as might be seen in complete biliary obstruction. | View Page |
| The bacterial species shown growing on 5% sheep blood agar was recovered from the spun sediment of a midstream urine specimen after 24 hours incubation at 35C. Each of the following tests would be useful in supporting the presumptive identification of Enterococcus species except: | View Page |
| PYR Differential As mentioned before, the spot PYR test is commonly performed to separate Enterococcus species (positive reaction) from the Group D streptococci (S. bovis, S. equinus), which are negative.It should be remembered that Streptococcus pyogenes (group A) also produces PYR; therefore, additional characteristics such as beta hemolysis are important.Some species of Aerococcus and Gemella are also PYR-positive; however, they can be suspected if large cocci in tetrads or clusters are observed on gram stain.These species are rare isolates in most clinical practices. | View Page |
| Colony Morphology The growth observed on the anaerobic blood agar plate after 48 hours incubation (see upper photograph), revealed a spreading colony. The spreading nature of the colony is better observed in the close-in photograph (lower). No growth was observed on subcultures incubated aerobically indicating that this isolate is truly an anaerobe (although aerotolerance studies would be needed for confirmation). The spreading nature of the colony and the lack of hemolysis are highly suggestive of Clostridium septicum. However, biochemical confirmation is necessary. | View Page |
| Staph on BA The photomicrograph of the surface of a 5% sheep blood agar illustrates the colonies that grew out of the foot drainage after 24 hours at 35C. They are entire, convex, smooth, and have a slight yellow pigmentation. Hemolysis is not observed. A gram stain was prepared from one of the isolated colonies. | View Page |
| Illustrated in the upper photograph are tiny pinpoint 24-hour colonies recovered from one of the splenic abscesses. The wide zones of beta hemolysis are better seen in the close-in view of the 36 hour culture shown in the lower photograph.
Streptococcus milleri (anginosus) can be suspected if one of the following odors is detected: | View Page |
| Group A Strep A Disk/SXT In follow up to the previous question, the upper image again illustrates the colonies recovered from the blood culture bottle. The colonies are small, transluscent, gray-yellow, and surrounded by a wide zone of beta hemolysis.The size of the colonies compared to the zones of hemolysis suggests a group A streptococcus.The susceptibility to bacitracin (zone of inhibition around the "A" disk)(lower photograph) is virtually diagnostic of a group A streptococcus.The absence of a zone of inhibition around the SXT disk indicates resitance to sulfamethoxazole/ trimethoprim. SXT resistance is also shared by group B streptococci, which are, however, resistant to bacitracin.The resistance to SXT is used for the primary recovery of groups A and B streptococci from specimens with mixed culture. Their resistance allows them to selectively grow out from contaminating bacteria that are inhibited by this antibiotic. | View Page |
| Thus, in follow-up to the previous discussion, the reaction shown in the photograph establishes the identification of a group A, beta hemolytic streptococcus. | View Page |
| Shown in the photograph is a close-in view of the colony growth after 48 hours incubation. Possible presumptive identifications suggested by the colonies observed include: | View Page |
| Colony Morphology Photograph of the surface of blood agar after 24 hours incubation at 35C in 10% CO2, on which are growing tiny, translucent, gray colonies surrounded by a narrow zone of "soft" beta hemolysis.There was no growth on the MacConkey plate. | View Page |
| Table 3: Testing the Serum with Known Red Cells (Reverse Typing) It has been demonstrated that antibodies occur predictably in the sera of all normal adults in association with the ABO antigens. Demonstration of these antibodies is therefore necessary for definitive classification of an individual’s ABO cell type. The individual’s serum is therefore tested against reagent red cells containing known antigens. Patient ABO Blood Group Patient Serum Tested with Known Reagent Cells A Cells B Cells A 0 4+ B 4+ 0 O 4+ 4+ AB 0 0 + = agglutination (graded 1+ to 4+)0 = no agglutination or hemolysis | View Page |
| Agglutination Reactions Antibodies of the ABO system cause agglutination of saline-suspended red cells at 4°C to 20°C. Heating to 37° weakens the reaction. “Naturally” occurring ABO antibodies may not be strong enough to agglutinate cells without centrifugation. Thus, testing serum for the presence of anti-A or anti-B has classically been performed using the tube system in which serum and cells added to a test tube are centrifuged and then evaluated for agglutination. A slide test has also been performed for forward reactions. Although tube tests are still in wide use, newer systems utilizing other technology such as gel agglutination are becoming more prevalent. The image on this page illustrates agglutination reactions observed with the tube system, from 4+ in the topmost image, to 0 in the lowest image. ABO reactions should be strong. Weak or missing reactions occur, but must be "resolved" before blood products can be released.4+ agglutination: Red blood cell button is a solid agglutinate; clear background.3+ agglutination: Red blood cell button breaks into several large agglutinates; clear background.2+ agglutination: Red blood cell button breaks into many medium-sized agglutinates; clear background; no free red blood cells.1+ agglutination: Red blood cell button breaks into many small clumps barely visible macroscopically; background is turbid; many free red blood cells.Negative: No agglutinated red blood cells present; red cells are observed flowing off the red blood cell button during the process of grading.Other reaction which may occur are the mixed-field reaction, in which mixtures of agglutinated and unagglutinated red blood are present; and hemolysis, in which red cells are hemolyzed by the antibody. Both of these patterns are considered positive reactions. | View Page |
| Testing the Red Cells With Known Antisera Patient Red Cells Tested With Known Antisera ABO Antigens Present on Red Cell Anti-A Anti-B Anti-A,B 4+ 0 4+ A 0 4+ 4+ B 0 0 0 Neither A nor B 4+ 4+ 4+ A and B + = agglutination (graded 1+ to 4+) 0 = no agglutination or hemolysis | View Page |
| Reverse Typing Reverse typing refers to the testing of a patient's serum for the presence of ABO antibodies. The patient's serum is mixed with known red cells in a test tube. A specified number of drops of patient serum are placed into each of three properly labeled tubes. A specified number of drops of known A1 cells are added to the A tube, and a specified number of drops of known B cells are added to the B tube. The tubes are mixed by gently shaking, centrifuged, and observed against a well-lit white background for the presence of hemolysis in the supernatant fluid. The cell button is then gently dispersed and inspected for agglutination, again using a well-lit background. Hemolysis or agglutination is a positive reaction. The expected reactions can be seen in the table on the following page. | View Page |
| Testing Patient Serum With Known Reagent Red Cells (Reverse Grouping) Patient Serum Tested With Known Reagent Red Cells Antibodies Present in Serum A1 Cells B Cells 0 4+ Anti-B 4+ 0 Anti-A 4+ 4+ Anti-A and Anti-B 0 0 No ABO antibodies present + = agglutination (graded 1+ to 4+) 0 = no agglutination or hemolysis | View Page |
| Interpretation of ABO Group We can use the forward type together with the reverse type to interpret the ABO group. The expected reaction are as follows: Red Cells Tested With Known Antisera Serum Tested With Known Red Cells Interpretation of ABO Group Anti-A Anti-B Anti-A,B A1 Cells B Cells 4+ 0 4+ 0 4+ A 0 4+ 4+ 4+ 0 B 0 0 0 4+ 4+ O 4+ 4+ 4+ 0 0 AB + = agglutination (graded 1+ to 4+) 0 = no agglutination or hemolysis | View Page |
| Case Marcie Moore was a phlebotomist at a community hospital in Atlanta. It was her week to collect the pediatric unit and she was on her way to the room of a newborn for which she had just received orders to draw a STAT BMP (chem-7) and bilirubin. After informing the mother of the baby about the test she needed to perform, Marcie set up to perform a heel stick on the baby. Marcie chose a site on the outer edge of the heel on the bottom of the baby’s foot ( the correct area for a heel stick) and made a small incision with a Tenderfoot lancet after cleaning the site well with alcohol.She immediately began collecting the blood in the correct tube for the BMP and bilirubin. Blood flow was not strong so Marcie squeezed the baby’s foot a little to help the blood come out faster – the newborn was screaming and Marcie could tell it was making the mother uncomfortable. She wanted to hurry and get done so the mother could hold the baby.After the chemistry tech ran the blood tests on the tube, she informed Marcie that the newborn had a panic potassium level which did not coincide with the previous blood work on the newborn. Also the chemistry instrument could not perform the bilirubin due to hemolysis. Marcie was asked to recollect the specimen. | View Page |
| Discussion Hemolysis can easily be caused by improper phlebotomy techniques. Hemolysis occurs when RBCs are broken up and hemoglobin is released into the plasma, causing it to become pink rather than its natural straw color. Hemolysis can occur by using too small a needle, pulling a syringe plunger too rapidly, expelling blood vigorously into a tube, or shaking a tube of blood too hard. Hemolysis can cause falsely increased potassium, magnesium, iron, and ammonia levels, and other aberrant lab results.In this case, Marcie did not properly wipe the site with gauze after cleaning it with alcohol, and alcohol contacting the blood could have caused RBCs to break up or hemolyze. Marcie also squeezed the baby’s foot too hard, causing hemolysis.Relevant topics:Site selection and preparation, Heelstick: Puncture, Hemolysis, Causes of hemolysis | View Page |
| Syringe - Transferring blood to collection tubes contd It is important to transfer the blood to appropriate tubes immediately because a syringe contains no anticoagulant, and the transfer must be complete before blood starts to clot.Do not push the plunger while transferring blood into a collection tube.
This may cause hemolysis, ruining the specimen. | View Page |
| Heelstick - specimen collection Collect the blood into the appropriate tube.Do not: Squeeze the infant’s foot too tightly and wipe with alcohol during the collection.These actions could result in hemolysis (breakdown of the red blood cells), invalidating the test results. | View Page |
| Hemolysis Hemolysis means the breakup of fragile red blood cells within the specimen, and the release of their hemoglobin (the red oxygen carrying substance present within the red cells), and other substances, into the plasma.A hemolyzed specimen is one which has undergone hemolysis.
A hemolyzed specimen can be recognized after it is centrifuged by the red color of the plasma. | View Page |
| Causes of hemolysis Hemolysis can be caused by: Shaking the tube too hard.Using a needle that is too small.Pulling back too hard on a syringe plunger.Pushing on a syringe plunger too hard when expelling blood into a collection device.
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| G6PD deficiency A ten-year-old boy came to a physician's attention because of recent jaundice and icteric sclerae. The immediate laboratory work revealed: Hct 24%(normal 36%-47%), MCV 79.5 fl (normal 78-95fl),RDW 13%(normal 11.5-15.0%). His blood smear findings are reflected in these photomicrographs. Note particularly the spherocytes in the upper picture. Some resemble a half-blister with the other half of the cell containing solidly-staining hemoglobin. These are called eccentrocytes. When present, they should trigger a search for red cell hereditary G-6PD deficiency and the oxidant that triggered hemolysis. These morphological findings are only clues; specific testing for G-6PD deficiency should be performed. The blue arrows in the upper photomicrograph are directed toward solid-staining spherocytes in which the cell membrane is beaded by inclusions wrapped within the cell membrane, suggesting the remains of denatured hemoglobin. Included on the smear is a target cell, several acanthocytes, a smudge cell, and a few schistocytes. The lower photomicrograph is supravital staining of affected red blood cells, verifying the presence of Heinz bodies. This disorder was first recognized during the Korean war in 10% of black American soldiers given the antimalarial drug primiquine. | View Page |
| Reticulocyte identification Reticulocytes are red blood cells prematurely released from the bone marrow. On a Wright-Giemsa stained blood smear, they appear as polychromatic macrocytes. Their presence in the peripheral blood may suggest hemolysis or bleeding. Their presence is expressed as a percentage of the red cell count: newly born= 3-7%; up to one week of age=1-3%; >one week =0.3-1.8%. Automated or manual methods may be used to enumerate reticulocytes. In clinical context, retics must be separated from debris, precipated stain, Pappenheimer bodies, Howell-Jolly bodies, and Heinz bodies. | View Page |
| Intracellular RBC Inclusions-G6PD (continued) G6PD deficiency occurs in the same geographic distribution as malaria. It has been theorized that enzyme deficient cells are more resistant to malarial parasites than normal cells.When hemolysis is triggered, the appearance of the red blood cells is modulated by activity of the spleen.Spherocytes, schistocytes, and nucleated red blood cells may appear in the peripheral blood.Denatured hemoglobin removed by an active spleen may leave bite cells, identified by the arrows in this photomicrograph, suggesting the presence of G6PD deficiency. | View Page |
| Heinz body formation Heinz bodies are 1-3 um particles of denatured hemoglobin settling eccentrically, usually close to the red cell membrane. They are found in erythrocytes in unstable hemoglobin disorders, acute drug induced hemolysis, and following splenectomy. Their formation may be exaggerated by in-vitro incubation of a fresh blood sample with phenylhydrazine. Heinz bodies, as pictured here, are identified using a supra-vital stain, such as new methylene blue or cresyl violet. Bite cells, visible with Wright-Giemsa staining, are visual reminders that the spleen is functional and has pitted the aberrant chunk of hemoglobin from the circulating erythrocyte. | View Page |
| Cardiac hemolysis (Waring Blender Effect) Two photographs of a peripheral blood smear are submitted for review . The smears are from a 9-month-old baby with a heart valve replacement. In the upper photograph is a nucleated RBC and platelets are decreased. Nucleated red cells and occasional giant platelets indicate an active marrow response. In the process of forcing blood cells through the heart valve, erythrocytes are damaged, schistocytes are formed, and platelets are destroyed leading to thrombocytopenia. In the lower field are schistocytes, acanthocytes, echinocytes (burr cells), spherocytes, and the absence of platelets. The presence of burr cells could represent an artifact of smear preparation, but with the history of valve replacement, the red cell changes are likely the result of red cell damage as the cells circulate through the new valve. This situation is described as Waring Blender Effect because of damage to blood cells passing through the new valve, looking as if they had suffered the onslaught of a blender. Target cells and mild hypochromia may reflect iron deficiency through the loss of iron from destruction of RBC's. Iron loss through red cell destruction may be reflected in some hypochromia. | View Page |
| The cells marked by blue arrows in the photograph are associated with all of the following conditions except: | View Page |
| Hemolytic disease of the newborn Jaundice was recognized in a day-old infant. Notice particularly the size variation (anisocytosis) of the erythrocytes on the infant's peripheral smear. What does this observation mean? Does it provide immediate information that might serve as guidance in expediting diagnosis and treatment? Note that normal-sized red blood cells, microcytes, microspherocytes, macrocytes, and nucleated red blood cells are all present. Red cell variations are expected findings in healthy neonates, but the variations here are exaggerated. Hyposplenic functional features may appear, including acanthocytes, spherocytes, and possibly Howell-Jolly bodies, especially if hemolysis is particularly vigorous. A high (3-7%) reticulocyte count is not unusual during the first three or four days after birth, however, the marrow in this jaundiced infant is proliferating vigorously in response to hemolysis. A call for more red cells is urgent. Immature red cells (in the form of nucleated red cells) and red cells with stippling of RNA (basophilic stippling) are readily identified. Red cell maturation sequence has not been totally processed in the marrow nor is all residual red cell debris removed by the spleen. In the lower photograph are reticulocytes stained by supravital stain (new methylene blue). Basophilic stippling (specks of RNA) stains with both supravital stains and with routine Wright-Giemsa stain. | View Page |
| Spherocytes and reticulocytes The photograph represents peripheral blood smear findings in another patient with hereditary spherocytosis. The red cells vary in size (anisocytosis)with a mixture of microcytes (red cells with central pallor) and microspherocytes (red cells with central staining). Macrocytes are conspicuous, some staining light blue. They are immature erythrocytes (reticulocytes)released from the bone marrow early. The bone marrow, geared up for rapid cell release in response to severe hemolysis, expels young red blood cells into the circulation before completing their 24 hour maturation cycle. Hemolysis, jaundice, and gall stone formation disappear following splenectomy. Gallbladder and stone removal eliminate the right upper quadrant pain. A serious consideration, especially in children with hereditary spherocytosis, is hemolytic crisis. A viral infection may allow red blood cell destruction to continue unabated. Anemia of such sudden onset and severity may become catastrophic, with death as the outcome. Splenectomy removes this possibility. | View Page |
| Warm antibody hemolytic disease A 49-year-old male with pneumonia was treated with penicillin. He became jaundiced with yellow sclera. Observe the photograph of his peripheral blood smear. Anisocytosis was observed with pale-centered microcytes and polychromatophilic macrocytes. Since penicillin is a classic offender for autoimmune hemolytic disease, the clinician asked for an antihuman globulin (AHG) test, also known as the Coombs test. A positive AHG reaction occurs when the antibody stimulated by penicillin becomes attached to red blood cells. Hemolysis follows, leaving the patient with jaundice and a peripheral blood smear, as demonstrated in the photograph. | View Page |
| The photograph here is of a peripheral smear sent for hematologic review. No clinical information for the patient was sent with the slide. What is the first course of action that the reviewer should take to assist him/her in interpreting the findings on this blood smear? | View Page |
| The photograph is representative of the peripheral blood smear of a five-month-old immigrant from Asia. Her mother was concerned that the child was not eating well. Her spleen was palpable.The hemogram revealed the following:Hb 9.6g/dL (normal 12.0 - 16.0 g/dL)RBC 5.48 X 1012/L (normal 4.2 - 5.9 X 1012/LHCT 30.4% (normal 37 - 48%)MCV 55.4 fl (normal 86 - 98 fl)MCH 17.5 pg (normal 27 - 32 pg)MCHC 31.6 g/dL (normal 31 - 37 g/dL)RDW 34.9% (normal 11 - 15%)Reticulocyte count 10.9% (normal 0.5 - 1.5%)Select the most likely diagnosis based on the clinical information and peripheral blood findings. | View Page |
| Hb E disease (continued) The family (cited in the previous case history) was from a region of Thailand where the physician knew HbE carriers are prevalent. Homozygous hemoglobin 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. Hemoglobin E is uncommon in North America and in Europe, but with changing immigration patterns, hemoglobinopathy E cannot be ignored. Peripheral blood smear findings of target cells, microspherocytes, red cell hypochromia, a few red blood cell fragments, and nucleated red blood cells require evidence from hemoglobin electrophoresis to establish a diagnosis. Clinically, a very important and severe syndrome is hemoglobin E/beta thalassemia in which there is hemolysis requiring repeated transfusions. The patient has a severe anemia, low MCV (50's), and high RBC. This is characteristic of Hgb E/beta thalassemia. | View Page |
| Stomatocytes Stomatocytes are erythrocytes with a slit-like central pallor. Otherwise, they resemble typical RBC's in size and shape. Unless 10% or more of the RBC's are stomatocytes, their presence is probably artifactual. Stomatocytes form at a low blood acidic pH as seen in exposure to cationic detergents, and in patients receiving phenolthiazine. Hereditary stomatocytosis has some resemblance to hereditary spherocytosis, as stomatocytes may develop into spherocytes with further metamorphosis. In hereditary stomatocytosis, mild anemia and findings of on-going hemolysis should be evident if the condition presents as a clinical problem at all. | View Page |
| The blood study from which this smear was obtained revealed an MCV of 115 femtoliters (fl).Normal MCV values in adults= 80 - 90 fl.Normal MCV values in full-term infants= 98 -108 fl.Which of the following conditions may be indicated by the results seen on this peripheral blood smear? | View Page |
| Pre-analytical Errors Preanalytical Error What is it? How does it happen? What is the result? Hemolysis Red blood cells (RBCs) break and release contents of cell into plasma. Needle incorrectly positioned in vein; cells forced to squeeze through opening. Needle gauge too small; slow blood return into tube. Vigorous mixing or shaking of tube. Alcohol on skin that has not had sufficient time to dry. Some test results may be falsely elevated. (Potassium is especially affected by hemolysis.) Patient may have to be re-drawn. Clotted specimen Clumped or clotted cells in specimen that requires anticoagulated or whole blood Insufficient mixing of blood with anticoagulant in tube. Delay in mixing tube. Slow filling tube. Inaccurate test results for cell counts and clotting studies. Patient may have to be re-drawn. Tube filled to incorrect volume Too little or too much blood in tube. Tube removed from needle too quickly. Vacuum in tube has been compromised due to use of tube past the expiration date (Results in a short fill). Manual fill of tube may lead to over-fill. Test results may be unreliable due to dilution errors. Patient may have to be re-drawn. | View Page |
| Do Not Tamper With the Specimens A phlebotomist should not uncap a blood tube and pour blood between tubes or combine two partially filled tubes of blood into one. This may lead to over-fill of tubes and more importantly, invalid patient results. Combining two tubes with the same additive into one tube will alter the blood to anticoagulant ratio by doubling the amount of anticoagulant in the tube. When blood is being transferred from a syringe to a tube, the phlebotomist must not apply pressure to the plunger to force blood into the tube. This may cause over-filling of the tube and hemolysis of blood cells. With the aid of a transfer device, the tube will draw the amount of blood required to fill the tube based on the amount of vacuum in the tube. | View Page |
| Syringe The syringe and needle combination should be the last equipment option that is considered; it is not as safe a choice as the self-contained blood collection systems because it involves more manipulation. However, the phlebotomist may choose to use a syringe to prevent vein collapse if the phlebotomist thinks that the vein is too fragile to withstand the pressure exerted by the vacuum as it pulls blood into the collection tube. A transfer device aids in the safe transfer of blood from the syringe into blood collection tubes. During blood transfer, do not manually push plunger as this may cause hemolysis of the specimen. | View Page |
| Cleansing the Venipuncture Site The product used most often to cleanse and disinfect the site prior to venipuncture is 70% isopropyl alcohol in towelette form. Alternative cleansing agents available are chlorhexadine gluconate (chloraprep) and povidone-iodine which are used mainly for collection of blood cultures, blood alcohol specimens, or when the patient is sensitive to alcohol.The alcohol should be applied using a circular target motion, as demonstrated in the image. This technique pushes the bacteria away from the inside of the venipuncture site to the outside. The alcohol must be allowed to air dry for approximately one minute prior to venipuncture to properly disinfect site, prevent hemolysis of the specimen, and avoid discomfort for the patient. Gauze should be used when applying pressure to the venipuncture site immediately after the needle is withdrawn. Adequate pressure to stop bleeding is crucial to avoid formation of a hematoma or bruise. Cotton balls should not be used to apply pressure to stop bleeding because the clot formed may be dislodged by residual cotton fibers as the cotton ball is pulled away from the site.Paper tape or a bandage is used to cover the wound after bleeding has stopped to prevent disruption of the clot. | View Page |
| Venipuncture Procedure At a Glance Required Step Description Step #1 Wash your hands. Clean your hands with soap and water or gel cleanser. Step #2 Positively identify patient using unique identifiers. Ask the patient to state his/her first and last name; if the patient is unable to give you this information, ask the patient's caregiver to confirm the patient's name. A second unique identifier must also be used. Step #3 Special test requirements Determine if the test to be obtained has any special requirements. For example, should the patient be fasting? Is this a timed test? If any requirements are not met, consult with the caregiver to determine a course of action. Step #4 Prepare the patient Explain the procedure to the patient and obtain cooperation. Usually the patient will extend an arm. (This is a form of implied consent.) Position the arm for venipuncture; support the arm on a firm surface; the arm should be in a downward position. Step #5 Site determination The patient can make a fist, but should not pump the hand open and closed. Apply tourniquet Palpate the vein. Release the tourniquet and assemble appropriate equipment. Step #6 Aseptic technique Wear gloves that have not been altered in any way. Cleanse site with approved disinfectant. Allow the disinfectant to air-dry to avoid hemolysis of the specimen and discomfort to the patient. Step #7 Specimen collection Re-apply tourniquet about 3-4 inches above puncture site, insert needle, bevel-side up, at about a 30° angle, and collect specimens. Remove needle and immediately activate the safety device. Mix specimens by gentle inversion 5-10 times. Step #8 Patient care Apply direct pressure to stop bleeding at puncture site; do not have patient bend arm as this may cause a hematoma to form. After about 2 minutes, check the puncture site to verify that bleeding has stopped. Apply bandage if appropriate. Thank the patient for his/her cooperation. Step #9 Specimen labeling Label specimen(s) in the presence of the patient including all the information that is required by your facility. Check the labeled tubes a second time against the patient's wristband to verify labeling accuracy. A professional phlebotomist follows the procedure in the same way for every venipuncture. This ensures that none of the vital steps are omitted. The phlebotomist who is consistent in performance and who concentrates fully to obtain a quality specimen is an indispensable part of the healthcare team. | View Page |