UKMLA PLAB AMC USMLE Prometric MCQ

Question Number 1147

Question:
A 65 year old male with a history of a prosthetic mechanical heart valve is on long term treatment with coumadin receiving 5 mg a day.
He visits the coagulation clinic regularly for assessment.
Coumadin effectiveness is most appropriately assessed with

a) Platelet count
b) Clot retraction
c) Tourniquet test
d) Bleeding time
e) Prothrombin time (PT)