Automated chromogenic assay for the quantitative determination of unfractionated heparin (UFH) and low molecular weight heparin (LMWH) activity in human citrated plasma on Coagulation Systems when used in conjunction with HemosIL Heparin Calibrators. This assay is also intended for the measurement of direct FXa inhibitor concentrations (e.g. rivaroxaban, apixaban) in human citrated plasma.

Test principle

The Liquid Anti-Xa kit is a one stage chromogenic assay based on a synthetic chromogenic substrate and on Factor Xa inactivation. Heparin levels in patient plasma are measured automatically on coagulation systems. Heparin is analyzed as a complex with antithrombin present in the sample. The concentration of this complex is dependent on the availability of the patient’s endogenous antithrombin. When the Heparin – antithrombin complex is formed, two competing reactions take place. Rivaroxaban and apixaban directly inhibits Factor Xa activity independent of the antithrombin present. 1. Factor Xa is neutralized by heparin-antithrombin complex or directly by rivaroxaban and apixaban. 2. Residual Factor Xa is quantified with a synthetic chromogenic substrate. The paranitroaniline released is monitored kineticall at 405 nm and is inversely proportional to the heparin2 or rivaroxaban or apixaban level in the sample.

Reagents and Stability (opened)

Unopened reagents are stable until the expiration date shown on the vial when stored at 2-8°C.

Analyzer adaption: on request