American Board of Internal Medicine (ABIM) Certification Practice Exam

The primary aim of using activated protein C (APC) resistance assays is to detect factor V Leiden mutations. This test is critical because factor V Leiden is a genetic mutation that increases the risk of thrombosis by making the factor V protein resistant to inactivation by activated protein C. In patients with this mutation, the typical anticoagulant effect of APC is diminished, contributing to a higher propensity for clot formation.

The APC resistance assay measures how effectively activated protein C can prolong the clotting time in a patient's plasma. When resistance to APC is present, it indicates potential factor V Leiden mutations, and thus, it is a valuable tool for assessing the risk of venous thromboembolism in affected individuals.

In contrast, diagnosing acute hemolytic anemia, assessing renal function, and evaluating liver enzyme levels are not related to the mechanism by which APC resistance impacts coagulation pathways. These conditions require different diagnostic approaches and laboratory tests that are not specific to the evaluation of APC resistance.