Outline how the following tests assess coagulation:
a. Prothombin Time (PT)
b. Activated Partial Thromboplastin Time (APTT)
c. Activated Clotting Time (ACT)
d. Thromboelastography (TEG or ROTEM)
Many candidates incorrectly stated that the PT assessed the intrinsic system and that the APTT assessed the extrinsic system. This led to subsequent errors in relating a coagulation test to the appropriate coagulation factors that it assessed. Some candidates produced elaborate diagrams of the coagulation cascade in isolation without relating it to the question.
Curry, Andy NG, and JM Tom Pierce. "Conventional and near-patient tests of coagulation." Continuing Education in Anaesthesia, Critical Care and Pain 7.2 (2007): 45-50.
Raber, Martin N. "Coagulation tests." Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition (1990).