Improved thrombin-based assay for antithrombin-III

摘要

Thrombin-based assays are disclosed for determining antithrombin III (ATIII) present in a plasma sample. The assays involve a heparin derivative which, like heparin, effectively enhances the antithrombin activity of ATIII, but which, unlike heparin, does not substantially enhance the antithrombin activity of Heparin cofactor II (HCII). In the present assay, HCII contributes about 15% or less to the determined antithrombin activity. A lyophilized reagent composition, useful in the ATIII assay and comprising thrombin and a heparin derivative, or alternatively comprising thrombin and heparin, is also disclosed. A high-calibrator plasma reference useful in the ATIII assays and in assays for other plasma constituents is also disclosed. Kits employing the several aspects of the invention are disclosed as well. IMAGE