STA®-Liquid Anti-Xa: the solution of choice for UFH, LMWH and Fondaparinux monitoring

Heparin is an injectable anticoagulant widely used in emergency situations requiring immediate effect.
Different pharmaceutical grades of heparin have been developed, and can be classified into 3 main groups:

• Unfractionated Heparins (UFH),
• Low Molecular Weight Heparins (LMWH)
• Fondaparinux (FDX).

The main risks associated with those drugs are bleeding and heparin induced thrombocytopenia (HIT), a common prothrombotic complication of UFH and LMWH therapies.
Monitoring UFH anticoagulant activity is mandatory because of its unpredictable effect and high variations among patients. LMWH and Fondaparinux have to be monitored in special cases only, where risk of accumulation is high (renal deficiencies) or in case of unexplained bleeding events.
In order to prevent HIT, platelets monitoring is mandatory for UFH and LMWH in all cases.

The new STA®-Liquid Anti-Xa assay is the solution of choice for UFH, LMWH and Fondaparinux monitoring.
It is based on the inhibition of a known amount of factor Xa by the patient's sample heparin combined with antithrombin. The residual factor Xa activity assessed by a colorimetric test will be inversely proportional to the heparin concentration.
Unlike the aPTT, the anti-Xa assay is not influenced by additional coagulation factors of the intrinsic and common pathways and inhibitors. It is not affected by concomittant VKA therapy. It is less affected by other preanalytical variables such as anticoagulation, specimen collection and processing.

STA®-Liquid Anti-Xa main features are summarized in the table below: