CHAPTER 42: LABORATORY EVALUATION OF HEMOSTASIS

Question 1

(1) What happens if a coagulation specimen collection tube is underfilled?

a. The specimen clots and is useless
b. The specimen is hemolyzed and is useless
c. Clot-based test results are falsely prolonged
d. Chromogenic test results are falsely decreased

Answer 1

c. Clot-based test results are falsely prolonged

Question 2

(2) If you collect blood into a series of tubes, when in the sequence should the hemostasis (blue stopper) tube be filled?

a. After a lavender-topped or green-topped tube
b. First, or after a nonadditive tube
c. After a serum separator tube
d. Last

Answer 2

b. First, or after a nonadditive tube

Question 3

(3) What is the effect of hemolysis on a hemostasis specimen?

a. In vitro platelet and coagulation activation occur
b. The specimen is icteric or lipemic
c. Hemolysis has no effect
d. The specimen is clotted

Answer 3

a. In vitro platelet and coagulation activation occur

Question 4

(4) Most coagulation testing must be performed on PPP, which is plasma with a platelet count less than:

a. 1000/uL
b. 10,000/uL
c. 100,000/uL
d. 1,000,000/uL

Answer 4

b. 10,000/uL

Question 5

(5) You wish to obtain a 5-mL specimen of whole-blood/anticoagulant mixture. The patient’s hematocrit is 65%. What volume of anticoagulant should you use?

a. 0.32 mL
b. 0.5 mL
c. 0.64 mL
d. 0.68 mL

Answer 5

a. 0.32 mL

Question 6

(6) You perform whole-blood lumiaggregometry on a specimen from a patient who complains of easy bruising. Aggregation and secretion are diminished when the agonists, thrombin, ADP, arachidonic acid, and collagen are used. What is the most likely platelet abnormality?

a. Storage pool disorder
b. Aspirin-like syndrome
c. ADP receptor anomaly
d. Glanzmann thrombasthenia

Answer 6

a. Storage pool disorder

Question 7

(7) What is the reference assay for HIT?

a. Enzyme immunoassay
b. Serotonin release assay
c. Platelet lumiaggregometry
d. Washed platelet aggregation

Answer 7

b. Serotonin release assay

Question 8

(8) What agonist is used in platelet aggregometry to detect VWD?

a. Arachidonic acid
b. Ristocetin
c. Collagen
d. ADP

Answer 8

b. Ristocetin

Question 9

(9) Deficiency of which single factor is likely when the PT result is prolonged and the PTT result is normal?

a. Factor V
b. Factor VII
c. Factor VIII
d. Prothrombin

Answer 9

b. Factor VII

Question 10

(10) A prolonged PT, a low factor VII level, but a normal factor V level are characteristic of an acquired coagulopathy associated with which of the following?

a. Hemophilia
b. Liver disease
c. Thrombocytopenia
d. Vitamin K deficiency

Answer 10

d. Vitamin K deficiency

Question 11

(11) The patient has deep vein thrombosis. The PTT is prolonged and is not corrected in an immediate mix of patient plasma with an equal part of normal plasma. What is the presumed condition?

a. Factor VIII inhibitor
b. Lupus anticoagulant
c. Factor VIII deficiency
d. Factor V Leiden mutation

Answer 11

b. Lupus anticoagulant

Question 12

(12) What condition causes the most pronounced elevation in the result of the quantitative D-dimer assay?

a. Deep vein thrombosis
b. Fibrinogen deficiency
c. Paraproteinemia
d. DIC

Answer 12

d. DIC

Question 13

(13) What is the name given to the type of assay that uses a synthetic polypeptide substrate that releases a chromophore on digestion by its serine protease?

a. Clot-based assay
b. Molecular diagnostic assay
c. Fluorescence immunoassay
d. Chromogenic substrate assay

Answer 13

d. Chromogenic substrate assay

Question 14

(14) What component of the fibrinolytic process binds and neutralizes free plasmin?

a. PAI-1
b. TPA
c. α2-Antiplasmin
d. Urokinase

Answer 14

c. α2-Antiplasmin