[W7] Assessing Haemostasis

Question 1

What are the 5 steps of haemostasis?

Answer 1

Vessel spasm, platelet plug formation, coagulation, clot retraction, clot dissolution.

Question 2

What factor converts fibrinogen to fibrin?

Answer 2

Thrombin.

Question 3

What mediates platelet adhesion?

Answer 3

vWF and GPIb.

Question 4

What receptor is essential for platelet aggregation?

Answer 4

αIIbβ3 (GPIIb/IIIa).

Question 5

What pathway is assessed by PT?

Answer 5

Extrinsic pathway.

Question 6

What does aPTT assess?

Answer 6

Intrinsic pathway.

Question 7

What activates plasmin from plasminogen?

Answer 7

tPA (tissue plasminogen activator).

Question 8

What are petechiae?

Answer 8

<3mm red-purple spots due to capillary bleeding.

Question 9

What bleeding feature is more common in coagulation disorders than platelet disorders?

Answer 9

Haemarthrosis.

Question 10

What test replaces bleeding time for platelet function?

Answer 10

PFA-100.

Question 11

What does a raised D-dimer indicate?

Answer 11

Recent fibrin breakdown – suggests thrombosis but not specific.

Question 12

What test result pattern suggests DIC?

Answer 12

↓ platelets, ↑ PT, ↑ aPTT, ↑ TT.

Question 13

What drug is monitored using PT/INR?

Answer 13

Warfarin.

Question 14

What drug can cause prolonged TT, PT, and aPTT?

Answer 14

Heparin.