Innovance Antithrombin by Siemens Healthcare is a new chromogenic test for the automatic quantification of functionally active antithrombin in human citrated plasma. In contrast to antithrombin activity tests based on the inhibition of the coagulation factor thrombin, Innovance Antithrombin determines the activity of the antithrombin protein through the inhibition of coagulation factor Xa. This prevents distortion of the test result if a patient was given specific medication to prevent or treat thromboses, such as hirudin or other thrombin inhibitors. Innovance Antithrombin can be used with the automatic coagulation measuring devices from Siemens such as BCS and BCS XP as well as Sysmex CA-500, Sysmex CA-1500 and Sysmex CA-7000. The new test is also suitable for diagnosing congenital or acquired antithrombin deficiencies which are known to be linked with an increased risk of thrombosis.
The test kit components are ready for use and therefore especially fast and easy to use. The test is based on a chromogenic measurement principle. Citrated plasma is mixed with a surplus of coagulation factor Xa. If heparin is present, part of coagulation factor Xa is bonded and deactivated by the antithrombin present in the specimen. Surplus, uninhibited coagulation factor Xa then splits a chromogenic substrate. In this process, coloring is released, the concentration of which is detected with a photometer. The higher the concentration of the produced coloring, the higher was the quantity of uninhibited coagulation factor Xa and the lower was the concentration of functionally active antithrombin originally present in the plasma specimen.