A patient presents with a history of recurrent venous thromboembolism. Which of the following laboratory tests would be most useful in diagnosing an underlying hypercoagulable state due to a genetic defect?

A Prothrombin time (PT)
B Activated partial thromboplastin time (aPTT)
C Antithrombin III activity assay
D Factor V Leiden mutation analysis ✓

Explanation

Factor V Leiden is a common genetic mutation that leads to an increased risk of venous thromboembolism due to resistance to activated protein C. Testing for this mutation can help diagnose an underlying hypercoagulable state.

Source

Williams Hematology
Hematology Hematology: Coagulation Disorders Hematology: Coagulation Disorders Hard MEDICAL Confidence: high