ACTICHROME® Heparin (anti-FXa

INTENDED USE
ACTICHROME® Heparin (anti-FXa) is a chromogenic assay intended for the quantitative determination of unfractionated and low molecular weight heparins in human plasma by measurement of factor Xa inhibition.

PRINCIPLE
The inhibitory effect of antithrombin III (AT-III) on thrombin, factor Xa and other coagulation serine proteases in plasma is increased several thousandfold by heparin. This inhibition accounts for the anticoagulant effect of heparin. The quantitative determination of plasma heparin levels by the
measurement of their anti-Xa activity is a necessary tool for monitoring treatment efficacy.

Low molecular weight heparin (LMWH) preparations appear to catalyze the reaction between factor Xa and AT-III more readily than the reaction between thrombin (FIIa) and AT-III. Unfractionated heparin (UFH) catalyzes both reactions equally. The factor Xa inhibition test is the most useful assay
covering the widest variety of heparin preparations. In the assay, the rate of factor Xa inhibition is directly proportional to the heparin concentration since both factor Xa and AT-III are in excess. The residual factor Xa activity is inversely proportional to the heparin concentration.1,2