Chromogenic assay for measuring Antithrombin in plasma with an Anti Xa method
liquid reagent technology


    • Ready-to-use liquid reagent technology
    • Human Factors
    • High on board stability
    • Insensitive for heparin
    • Automation protocols available


BIOPHENTM AT anti-(h)-Xa LRT assay is a kinetics method based on the inhibition of Factor Xa, which is at a constant concentration and in excess, by Antithrombin, in presence of heparin. The remaining Factor Xa is then measured by its amydolitic activity on a Factor Xa specific chromogenic substrate, which releases pNA. The amount of pNA generated is inversely proportional to the Antithrombin concentration present in the tested plasma.

Ordering information

Product Name Reference Package
BIOPHENTM AT-(h)-Xa (CE-IVD) 221123


 2 x 3 x 3 ml

2 x 4 x 7.5 ml

BIOPHENTM  Plasma Calibrator (CE-IVD) 222101 12 x 1 ml
BIOPHENTM  Normal Control Plasma (CE-IVD) 223201 12 x 1 ml
BIOPHENTM  Abnormal Control Plasma (CE-IVD) 223301 12 x 1 ml


  1. Tsiang M et al. Functional requirements for inhibition of Thrombin by Antithrombin III in the presence and absence of heparin. The journal of Biological Chemistry vol. 272, N°18 12024-12029 (1997).
  2. Odegard O R et al. Heparin cofactor activity measured with an amidolytic method. Thromb res 6, 287-294 (1975).
  3. Mann K.G. Biochemistry and Physiology of blood coagulation. Thrombosis and Haemostasis vol 82 N° 2 165-174 (1999).
  4. Demers C et al. An Antithrombin III assay based on factor Xa inhibition provides a more reliable test to identify congenital antithrombin III deficiency than an assay based on thrombin inhibition. Thromb Haemostas 69, 231- 235 (1993).
  5. Leslie B. et al. Investigation of the anticoagulant mechanism of a covalent antithrombin-heparin complex. The Journal of Biological Chemistry vol. 273 N° 52 34730-34736 (1999).
  6. Mortensen J.Z. Inherited ATIII deficiency. Fast and slow inactivation of thrombin and Factor Xa Thromb. Res., 33, 511-515 (1984).
  7. Tran T H et al. Influence of heparin cofactor II (HCII) in the determination of Antithrombin III (AT). Thromb Res 40, 571-576 (1985).
  8. Tollefsen D.M. Laboratory Diagnosis of Antitrhombin and Heparin Cofactor II deficiency. Seminars in Thromb haemost 16, 162-168 (1990).
  9. Andersson N-E et al. New chromogenic ATIII activity kit which is insensitive to heparin cofactor II and designed for use on automated instruments. Thromb Haemost 65, 912 (1991).