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.