26 Questions
What is the primary purpose of the Bethesda unit in coagulation testing?
To measure the activity of FVIII inhibitors
What is the recommended approach for detecting weak inhibitors using the Bethesda unit?
Prolonging the incubation period at lower temperatures or room temperature
What is the relationship between the inhibitor unit and predicted bleeding risk?
The inhibitor unit does not necessarily correlate with predicted bleeding risk
What is the recommended course of action if a plasma sample contains more than one unit of inhibitor per ml?
Repeat the test until the percent residual factor is close to 50%
What is the purpose of the Platelet Neutralization Procedure (PNP) in coagulation testing?
To detect the presence of lupus anticoagulant
How does the Platelet Neutralization Procedure (PNP) work to detect lupus anticoagulant?
By increasing the quantity of phospholipid in the test system, reducing the impact of the phospholipid-dependent anticoagulant
What is the expected result of the Platelet Neutralization Procedure (PNP) in the presence of lupus anticoagulant?
A shortened APTT of 3-5 seconds or more
What is the purpose of combining the patient's weak plasma with the suspension of ruptured platelets in the Platelet Neutralization Procedure (PNP)?
To provide a source of phospholipid for the test
What is the purpose of comparing the clotting time of the patient's sample with a similar mixture where the platelets are replaced with calcium chloride in the Platelet Neutralization Procedure (PNP)?
To detect the presence of lupus anticoagulant
Which of the following is a characteristic laboratory finding in Disseminated Intravascular Coagulation (DIC)?
Increased fibrin degradation products
What is the primary purpose of the Protamine Sulfate Dilution Test in coagulation analysis?
To detect the presence of fibrin monomers or fibrin degradation products
Which of the following is a common indication for DDAVP (desmopressin) therapy in coagulation disorders?
Recurrent venous thrombosis
How does liver disease affect coagulation test results during the anhepatic phase of liver transplantation?
Results in prolonged prothrombin time and activated partial thromboplastin time
What is the relationship between obesity and the risk of recurrent venous thrombosis?
Obesity is associated with an increased risk of recurrent venous thrombosis, but the significance is unclear
What is the primary cause of prolonged clotting times in Disseminated Intravascular Coagulation (DIC)?
Depletion of coagulation factors
What is the mechanism of action of DDAVP (desmopressin) in the treatment of von Willebrand disease?
Stimulates the release of von Willebrand factor from endothelial cells
Which of the following tests is used to determine the presence of lysis products in a sample?
Both A and B
What is the purpose of the Protamine Sulfate Dilution Test in coagulation studies?
To detect heparin contamination in a sample
In the context of coagulation disorders, what is a common cause of prolonged prothrombin time (PT) and activated partial thromboplastin time (aPTT)?
Liver disease
What is the recommended course of action if vitamin K administration does not correct a prolonged prothrombin time (PT)?
Perform additional tests to assess for liver disease
Which of the following tests is most specific for detecting intravascular fibrin formation?
Ethanol Gelation Test
In which condition would you expect to find a high level of D-dimers?
Disseminated Intravascular Coagulation (DIC)
What is the principle behind the Protamine Sulfate Dilution Test?
Protamine sulfate neutralizes heparin, allowing the detection of heparin-like inhibitors
Which of the following conditions is associated with a decreased level of plasminogen?
Liver disease (cirrhosis)
What is the purpose of the DDAVP (desmopressin) therapy?
To increase fibrinogen levels
Which test is considered less sensitive but more specific than the Protamine Sulfate Dilution Test for detecting heparin-like inhibitors?
Ethanol Gelation Test
Test your knowledge on coagulation factor deficiency using the substitution test method. Practice identifying missing factors based on APTT correction with aged serum and no correction with adsorbed plasma.
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