What is the primary mechanism by which heparin exerts its anticoagulant effect?

A Inhibition of thrombin generation
B Enhancement of fibrinolysis
C Activation of protein C
D Binding to and activating antithrombin III ✓

Explanation

Heparin works by binding to and activating antithrombin III, which then inhibits several coagulation factors, including thrombin and factor Xa.

Source

Harrison's Principles of Internal Medicine
Hematology Hematology: Coagulation Disorders Hematology: Coagulation Disorders Medium MEDICAL Confidence: high