An improved clinical assay for antithrombin III (heparin cofactor)

A method for determining antithrombin-III heparin cofactor activity that requires no defibrinogenation of plasma, can be used with heparinized samples, and is specific for antithrombin-III heparin cofactor activity was developed. The procedure requires minimal pipetting, uses small amounts of sample over a single short incubation period, and is relatively inexpensive. The antithrombin-III assay appears to be superior to other commercially available procedures when employed in the diagnosis of deficiencies and in the identification of decreased levels of antithrombin III associated with liver disease and thrombotic disorders.