Antithrombotic Therapies and Their Laboratory Assessment

Question 1

1. What is the PT/INR therapeutic range for Coumadin therapy when a patient has a mechanical heart valve?
   a. 1 to 2
   b. 2 to 3
   c. 2.5 to 3.5
   d. Coumadin is not indicated for patients with mechanical
   heart valves

Answer 1

c. 2.5 to 3.5

Question 2

2. Monitoring of a patient taking Coumadin showed that her
   anticoagulation results remained stable over a period of
   about 7 months. The frequency of her visits to the laboratory began to decrease, so the period between testing averaged 6 weeks. This new testing interval is:
   a. Acceptable for a patient with stable anticoagulation results
   after 6 months
   b. Unnecessary, because monitoring for patients taking oral
   anticoagulants can be discontinued entirely after 4 months
   of stable test results
   c. Too long even for a patient with previously stable test
   results; 4 weeks is the standard
   d. Acceptable as long as the patient performs self-monitoring daily using an approved home testing instrument and
   reports unacceptable results promptly to her physician

Answer 2

c. Too long even for a patient with previously stable test
results; 4 weeks is the standard

Question 3

3. What is the greatest advantage of point-of-care PT testing?
   a. It permits self-dosing of Coumadin
   b. It is inexpensive
   c. It is convenient
   d. It is precise

Answer 3

c. It is convenient

Question 4

4. You collect a citrated whole-blood specimen to monitor
   UFH therapy. What is the longest it may stand before the
   plasma must be separated from the cells?
   a. 1 hour
   b. 4 hours
   c. 24 hours
   d. Indefinitely

Answer 4

a. 1 hour

Question 5

5. What test is used to monitor high-dose UFH therapy in the
   cardiac catheterization lab?
   a. PT
   b. PTT
   c. Bleeding time
   d. ACT

Answer 5

d. ACT

Question 6

6. What test is used most often to monitor UFH therapy in
   the central laboratory?
   a. PT
   b. PTT
   c. ACT
   d. Chromogenic anti-factor Xa heparin assay

Answer 6

b. PTT

Question 7

7. What test is used most often to monitor LMWH therapy in
   the central laboratory?
   a. PT
   b. PTT
   c. ACT
   d. Chromogenic anti-factor Xa heparin assay

Answer 7

d. Chromogenic anti-factor Xa heparin assay

Question 8

8. What is an advantage of LMWH therapy over UFH therapy?
   a. It is cheaper
   b. It causes no bleeding
   c. It has a stable dose response
   d. There is no risk of HIT

Answer 8

c. It has a stable dose response

Question 9

9. In what situation is an intravenous DTI used?
   a. DVT
   b. HIT
   c. Any situation in which Coumadin could be used
   d. Uncomplicated AMI

Answer 9

b. HIT

Question 10

10. What laboratory test may be used to monitor intravenous
    DTI therapy when PTT results are unreliable?
    a. PT
    b. ECT
    c. Reptilase clotting time
    d. Chromogenic anti-factor Xa heparin assay

Answer 10

b. ECT

Question 11

11. What is the reference method for detecting aspirin or
    clopidogrel resistance?
    a. Platelet aggregometry
    b. AspirinWorks
    c. VerifyNow
    d. PFA-100

Answer 11

a. Platelet aggregometry

Question 12

12. What is the name of the measurable platelet activation
    metabolite used in the AspirinWorks assay to monitor aspirin resistance?
    a. 11-dehydrothromboxane B2
    b. Arachidonic acid
    c. Thromboxane A2
    d. Cyclooxygenase

Answer 12

a. 11-dehydrothromboxane B2

Question 13

13. Which of the following is an intravenous antiplatelet drug
    used in the cardiac catheterization laboratory?
    a. Abciximab
    b. Ticagrelor
    c. Prasugrel
    d. Clopidogrel

Answer 13

a. Abciximab

Question 14

14. Which of the following is a newly developed oral anticoagulant?
    a. Argatroban
    b. Lepirudin
    c. Bivalirudin
    d. Rivaroxaban

Answer 14

d. Rivaroxaban

Question 15

15. Which of the following is not a point-of-care instrument
    for the measurement of PT?
    a. CoaguChek XS PT
    b. Gem PCL Plus
    c. Cascade POC
    d. Multiplate

Answer 15

d. Multiplate