Human Antithrombin is derived from human plasma, purified through affinity chromatography and gel filtration chromatography methods, and subjected to S/D virus inactivation steps.

Human Antithrombin is a serine protease inhibitor that forms a complex with heparin, leading to the inactivation of factor IIa (thrombin) and factor Xa. The biochemical potency of heparin can be determined based on the catalytic dissociation rate of residual coagulation factors on the corresponding chromogenic substrates.