Description
Antithrombin III is found in normal serum at 15 mg per 100 ml. Found at higher levels in plasma than in serum because of complexing with thrombin during coagulation. Functions in the inhibition of the proteolytic enzymes involved in blood coagulation and fibrinolysis, including factor Xa, plasmin, thrombin, and trypsin. Potency is strongly enhanced by heparin. Clinically, reduced levels are indicative of hypercoagulability.