| 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 |
| In order to prevent a loss of viability in platelet concentrates during storage the pH must be maintained above: | View Page |
| Fresh frozen plasma should be used for which of the following: | View Page |
| Which of the following are not appropriate indications for the use of fresh frozen plasma: | View Page |
| Which of the following best describes the direct antiglobulin test principle: | View Page |
| Therapeutic hemapheresis may be used to treat all of the following except: | View Page |
| The following steps must be followed in preparation of a platelet concentrate: | View Page |
| Which of the following statements is not true about the Lewis blood group: | View Page |
| Fresh frozen plasma : | View Page |
| Which of the following is the proper storage temperature for fresh frozen plasma: | View Page |
| Hemapheresis is used to harvest all of the following: | View Page |
| A severe hemophiliac, with a Factor VIII activity of less than 1%, is actively bleeding due to a serious accident. The blood product of choice is: | View Page |
| Which of the following blood components will provide the best source of fibrinogen for a patient with hypofibrinogenemia: | View Page |
| Antibodies to which of the following are the most frequent cause of febrile transfusion reactions: | View Page |
| Which of the following analytes would not be significantly increased in a plasma sample as a result of hemolysis: | View Page |
| Which of the following anticoagulants will not produce a significant effect on calcium levels in plasma: | View Page |
| Which of the following thyroid function assays is affected least by pregnancy: | View Page |
| What additional fraction would be seen if plasma rather than serum was subjected to electrophoresis: | View Page |
| Which of the following contributes most to serum osmolality: | View Page |
| Which of the following is found in plasma but absent in serum: | View Page |
| What is the largest constituent of plasma nonprotein nitrogen: | View Page |
| The measurement of total glycosylated hemoglobin A1c is an effective means of assessing the average blood glucose levels: | View Page |
| Which one of the following statements about acetominophen metabolism is false? | View Page |
| Label these SPE scans. | View Page |
| The primary mechanism responsible for glomerular filtration is: | View Page |
| The product administered to treat Von Willebrands Disease is? | View Page |
| Secondary Hemostasis – The Extrinsic Pathway The shortest, and least complex of the three pathways, the extrinsic pathway primarily focuses on the interaction of tissue factor with factor VII, leading to the activation of factor VII. Tissue factor, a substance expressed on the surface of cells such as fibroblasts and macrophages found outside the vasculature, initiates coagulation when plasma contained within the vessel walls leaks outside the broken vessel, and comes into contact with these cells. The nomenclature, extrinsic pathway, comes from the fact that tissue factor is external to the vasculature. | View Page |
| The Fibrinolytic System Fibrin strands woven into the clot structure are cleaved into soluble fibrin fragments, and then removed by macrophages. The action of fibrinolysis also serves to restore blood flow into the area that had been sealed off, helping to promote further healing. Fibrinolysis is mediated by a proteolytic enzyme called plasmin. Plasminogen is the inactive precursor form of plasmin that is found in plasma. Plasmin takes on fibrinolytic properties after activation, digesting both fibrin and fibrinogen. Inhibitors act to control the process, serving as a check and balance system for fibrinolytic activities. | View Page |
| Collecting Blood Specimens for Coagulation Testing The specimen of choice for coagulation testing is plasma. Venous blood is drawn into a 3.2% buffered sodium citrate tube (blue top tube), yielding a whole blood sample with a 9:1 blood to anticoagulant ratio. Inadequate filling of the collection tube will decrease this ratio, and may affect test results. A blue top tube used for coagulation testing should be drawn before any other tubes containing additives. This includes tubes containing other anticoagulants and/or plastic serum tubes containing clot activators. A serum tube that does not contain an additive can be collected before the blue top tube. If a winged blood collection set is used in drawing a specimen for coagulation testing, a discard tube should be drawn first. The discard tube must be used to fill the blood collection tubing dead space to assure that the proper anticoagulant/blood ratio is maintained, but the discard tube does not need to be completely filled. The discard tube should be a nonadditive or a coagulation tube. If a blood specimen used for coagulation testing must be collected from an indwelling line that may contain heparin, the line should be flushed with 5 mL of saline, and the first 5 mL of blood or 6-times the line volume (dead space volume of the catheter) be drawn off and discarded before the coagulation tube is filled. | View Page |
| Which of the following statements is incorrect? | View Page |
| Fibrin/Fibrinogen Degradation Products and D-dimers The presence of D-dimers in plasma or whole blood indicates that fibrin has been formed and degraded (fibrinolysis). Plasmin can also degrade intact fibrinogen, generating fibrinogen degradation products that are detected in fibrin/fibrinogen degradation products (FDP) assays. D-dimers and FDP can become elevated whenever the coagulation and fibrinolytic systems are activated. The presence of D-dimer confirms that both thrombin and plasmin have been generated since it can only be produced as the result of the plasmin degradation of fibrin. This makes the test for D-dimers more specific for fibrinolysis than the FDP test that also detects the products of the direct proteolysis of fibrinogen (fibrinogenolysis).The D-dimer test can be useful in the diagnosis of deep venous thrombosis (DVT) or pulmonary embolism (PE), two forms of venous thromboembolism (VTE). When the test is being used for this purpose, it is important that D-dimer levels are accurately measured and accurately reported because of the serious nature of this clinical decision. If the test is positive in a patient suspected to have DVT or PE, clinicians proceed with further diagnostic tests. If the test is negative, depending on the clinical situation and the sensitivity of the D-dimer assay, DVT or PE is considered unlikely and further diagnostic tests for DVT or PE might not be pursued. D-dimer is a sensitive, but not specific, diagnostic test for disseminated intravascular coagulation, and an indicator of increased risk of future myocardial infarction in patients evaluated for chest pain. | View Page |
| Tests of Hemostatic Function - Mixing Studies Performed after an unexpected, prolonged PT or APTT is encountered to determine if the problem stems from a factor deficiency or the presence of an inhibitor. To perform the test, the patients’ plasma is mixed with an equal volume of pooled normal plasma, and then a PT and APTT are performed off the mixture. If the addition of the pooled plasma brings the resultant values into normal range, then the pooled plasma contained factors the patient's sample was deficient in, and the patient has a factor deficiency. If the results are not “corrected” or brought back into normal range after the addition of pooled normal plasma, then an inhibitor may be present. The next step in the diagnostic sequence of events, if correction has occurred, is to perform a factor assay, to determine which specific factor is lacking. | View Page |
| Tests of Hemostatic Function - Factor Assays Used to determine the cause of an unexpected, prolonged PT or APTT.
This test is performed after mixing studies have been run, because factor assays are able to identify specific factor deficiencies or inhibitors.
Think of mixing studies as being the screening test, while factor assays are confirmatory tests for specific factor deficiencies.
The test itself is involves performing a PT and APTT, except that plasma known to be deficient in a specific factor type is combined with the patients plasma, comparing the resultant time to a standard curve.
The percent of activity, and amount of correction with normal plasma determines the specific factor deficiencies.
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| Coagulation Disorders - Acquired Disseminated Intravascular Coagulation (DIC) is best described as a disorder of consumption, because clotting factors are depleted from the blood. Basically, clotting occurs randomly throughout the body, as opposed to just in the localized areas where vascular damage has occurred, consuming clotting factors and other components such as platelets in the process. Symptoms may range from a mild bleed, to severe, profuse bleeding, primarily dependant upon the availability of clotting factors. As more and more coagulation factors and components are consumed, the disorder progresses and symptoms worsen. Most heavily impacted are the levels of factors I, V, and VIII as well as the number of available platelets. Clinically, DIC is detected via an elevated (positive) FDP, positive D-dimer test, a prolonged PT and APTT, plus the manifestation of hemorrhagic episodes. DIC is diagnosed as two primary types, acute and chronic. Acute DIC manifests in a few hours or a few days, has a high mortality rate, and is seen in infections, obstetric complications, liver disease, and tissue injury. Chronic DIC is a secondary condition to some other disease state. Once you treat the primary disease, this type of DIC will go away. Treatment is often factor replacement therapy through the use of fresh frozen plasma and/or cryoprecipitate. | View Page |
| Coagulation Disorders and Liver Disease The liver is the site of production for the vast majority of our clotting factors. Therefore, impaired liver function could adversely affect these hemostatic proteins. Some early indicators of a potential liver problem include: An increase in factor VIII. It is not produced in the liver and will be present in elevated numbers as the body attempts to compensate. The PT is sensitive to liver function, so an unexpected, prolonged PT should be evaluated. A lack of fibrinogen is often indicative of severe liver disease. It is difficult to treat liver disease, so therapy typically centers around replacing the missing factors by way of administration of fresh frozen plasma. | 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 |
| Basic metabolic panel (BMP) Consists of an electrolyte panel, plus:
Blood urea nitrogen (BUN), which a measure of renal function.
Creatinine (Creat), which also measures renal function
Glucose, the most important blood sugar, and
Calcium.
Run on serum or plasma
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| Lipid panel Cholesterol
High density lipoprotein
Low density lipoproteinTriglycerides
Lipid profile is run on serum or plasma.
It requires a 14 hour fast prior to collection. | View Page |
| Electrolytes panel (Lytes) Blood is tested for the most important electrolytes (salts):
Sodium (Na)
Potassium (K)
Chloride (Cl)
Carbon dioxide (CO2)Can be run on serum or plasma.
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| Green top tubes Contain either sodium or lithium heparin.Used for tests requiring whole blood or plasma such as ammonia or whole blood potassium.
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| 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 |
| Clots Blood clots when the coagulation factor proteins within the plasma are activated.Blood starts to clot almost immediately after it is drawn unless it is exposed to an anticoagulant.Clots within the blood specimen, even if not visible to the naked eye, will yield inaccurate results. | View Page |
| Plasma drugs and toxins Drugs and toxins including therapeutic drugs and drugs of abuse may be present in the plasma.
Other substances too numerous to mention are also present in plasma.
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| Plasma Plasma and formed elements stay mixed in circulating blood.
When centrifuged (or spun down), blood is separated into plasma, and formed elements including red blood cells. The plasma separator tube shown here has a barrier to maintain separation of plasma and cellular elements during centrifugation and storage.
The red cell layer also includes a relatively small amount of platelets and white blood cells, not visible in the photo on the right.
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| Plasma components Plasma is the liquid portion of the blood. It contains many substances including:Water
Electrolytes
Sugars
Proteins
Lipids
Drugs & Toxins
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| Plasma water Water (HĢ0) makes up the majority of the blood plasma. | View Page |
| Plasma water continued Water is the largest component of plasma, and makes up about 53% of whole blood.
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| Plasma electrolytes Electrolytes are salts dissolved in water, including:Sodium (Na)
Potassium (K)
Chloride (Cl)
Bicarbonate (CO2).
Calcium (Ca) | View Page |
| Plasma sugars Sugars are also dissolved in the plasma. By far the most important is glucose.
Blood glucose is increased in diabetes mellitus, and decreased in hypoglycemia.
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| Plasma proteins Numerous types of proteins are dispersed in the plasma. These include:
Coagulation proteins (blood clotting factors), which, if activated, will form a blood clot , and
Serum proteins, which are left dispersed in liquid after the clot is formed. Serum proteins include:
Albumin, a marker of nutrition, and
Globulins, or antibodies. | View Page |
| Whole blood: components Circulating whole blood is a mixture of:
Plasma (which contains fluid, proteins, and lipids), and
Formed elements, consisting of red cells, white cells, and platelets.
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| Serum Serum is the fluid that is left over the coagulum after the specimen is centrifuged (spun down).
Serum contains all the same substances as plasma, except for the coagulation proteins, which are left behind in the blood clot.
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| Plasma lipids Lipids are fats dispersed in plasma. They include:
Triglycerides
Cholesterol
Lipoproteins
The amount and ratios of various lipids in the blood will determine a person’s risk of getting coronary artery disease.
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| The upper photograph of a peripheral blood smear reveals RBC rouleaux formation. Nucleated cells evident in both upper and lower photographs comprise approximately 5% of the total white blood cell count. The most probable underlying condition is: | View Page |
| Platelet satellites (marked in the photograph) may account for low platelet counts as determined by electronic counters. Satellitosis is initiated by: | View Page |
| Approximately 10% of the circulating white cells were similar to the one seen in the photograph. The patient was 42 years old and visited his physician because of recent bruising. Note the absence of platelets on the smear. Possible associated conditions include: | View Page |
| Multiple myeloma Plasma cells are uncommonly observed in the peripheral blood smear.They are normal constituents of lymph nodes, spleen, connective tissue and bone marrow. The presence of plasma cells in the peripheral blood is indicative of a large number of conditions mostly related to infections , immune disorders, malignancies, toxic exposures, hypersensitivity reactions and their responses.Although mature plasma cells have a distinct appearance, they still may be confused morphologically with immature plasma cells and other cells with inclusions, reactive changes or nucleated red bloods cell with altered identities.In the upper and lower photographs are plasma cells with features mindful of myeloma cellsThe large myeloma cell in the upper photograph has an eccentric immature nucleus with a muddy chromatin pattern.Note also clumping and stacking of the erythrocytes, bordering on rouleaux formation ,implicating an increase in plasma gamma globulin.The plasma cell with the double nucleus in the lower photograph is particularly suggestive of myeloma.Further studies are in order including a bone marrow examination where at least 30% of bone marrow cells should be variations of mature and immature plasma cells.Serum electrophoresis will reveal a monoclonal globulin spike, and light chains in excess of 1.0 gm/24 hours may be seen in the urine.The presence of lytic bone lesions is a convincing clinical clue.With these findings in combination, a diagnosis of myeloma can be made with assurance. | View Page |