Leiden

Here’s a little coagulation quiz to start your morning.

1. Which of the following initiates the coagulation cascade IN VIVO?

A. Factor XII
B. Thrombin
C. Tissue factor
D. Factor X
E. Prekallikrein


2. What does von Willebrand factor do?

A. Binds platelets to each other
B. Binds platelets to the subendothelium
C. Binds platelets to the phospholipid surface
D. Carries factor VII
E. Cleaves factor V


3. Which of the following is true?

A. The extrinsic system is activated first, and then the intrinsic system is turned on later
B. The intrinsic system is weak and short-lived
C. The extrinsic system is only important in vitro
D. Factors V and VII are only important in vitro


4. Which of the following anti-clotting substances acts on factors V and VIII?

A. ATIII
B. Protein C
C. TFPI
D. Plasmin
E. t-PA


5. Which of the following is a cofactor?

A. XII
B. X
C. VIII
D. VII
E. II


6. What are the ingredients in a PTT?

A.  Plasma + phospholipid + calcium
B. Plasma + thromboplastin + calcium
C. Plasma + phospholipid + thromboplastin
D. Plasma + thrombin + calcium
E. Plasma + plasmin + calcium


7. Which test evaluates the extrinsic pathway?

A. PT (INR)
B. PTT
C. TT
D. Closure time
E. Bleeding time


8. Which of the following is true regarding the bleeding time?

A. It is a highly reliable and reproducible test
B. The sample is evaluated using an optical densitometer
C. It evaluates platelet function in vivo
D. It is a commonly ordered test
E. It evaluates the coagulation system


9. What is the most common inherited bleeding disorder?

A. von Willebrand’s disease
B. Hemophilia A
C. Hemophilia B
D. Factor V Leiden
E. TTP


10. Which disorders may show “factor-type” bleeding?

A. von Willebrand’s disease
B. Hemophilia A
C. Both
D. Neither


11. Patients with which of the following diseases may have a normal PTT?

A. von Willebrand’s disease
B. Hemophilia A
C. Hemophilia B
D. Factor V Leiden


12. TTP:

A. May present with CNS deficits
B. Is caused by a toxin produced by E. coli
C. Is treated supportively
D. Does not show a microangiopathic blood picture

Answers: 1. C, 2. B, 3. A, 4. B, 5. C, 6. A, 7. A, 8. C, 9. A, 10. C, 11. A,D 12. A

The gorgeous photo of Leiden (as in Factor V Leiden) was taken by Motumboe (http://www.flickr.com/photos/motumboe/2709667509/).