Special Precautions/Comments:

Interference: The use of haemolysed and lipaemic samples should be avoided.

Interpretation: B2GP1 antibodies should not be relied upon as a diagnostic tool but must be used in conjunction with evaluation of clinical symptoms. B2GP1 antibodies can be found without a clinical antiphospholipid syndrome [2]. Lupus anticoagulant (DRVVT) must be checked in addition. Antibodies should be repeated at least 6 weeks apart to provide evidence of a persistent autoantibody present [2].

Method: Fluorescence Enzyme Immunoassay (FEIA). Calibration: N/A. EQA scheme: UK NEQAS Scheme for Phospholipid antibodies. IQC: Commercial preparation.

Additional Information:

Indication: Anti-phospholipid syndrome

Background Information: Beta-2-Glycoprotein 1 (also known as apolipoprotein H) is a 50Kda beta-2-globulin found to inhibit the intrinsic coagulation pathway. Beta-2-Glycoprotein 1 is one of the major targets for anti-phospholipid antibodies found in anti-phospholipid syndrome [1]. Anti-B2GP1 antibodies are associated with antiphospholipid syndrome where patients suffer from venous and arterial thrombosis particularly in recurrent unexplained thrombocytopenia, recurrent foetal loss, myocardial infarction and recurrent stroke [2]. These symptoms are often present in cases of systemic lupus erythematosus (SLE) and in many other conditions [2]. The measurement of beta-2-glycoprotein antibodies is of most use in patients suspected of having antiphospholipid syndrome but who have negative results for lupus anticoagulant and anti-cardiolipin antibodies [2]. There is no current evidence that testing for anti-B2GP1 provides any additional diagnostic benefit of anti-cardiolipin antibodies [3].

References: Wong RCW, et al. Consensus guidelines on anti-beta 2 glycoprotein I testing and reporting. Pathology. 2008. 40(1):58-63. Sahin M, et al. Antibodies to beta 2-glycoprotein-I: relation of anticardiolipin antibodies with clinical and laboratory parameters in patients with SLE. Clin Biochem. 2007. 40(8):526-530. PRU Handbook of Autoimmunity. 4th Edition. 2007. Miyakis S, et al. International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome(APS). J Thrombosis and haemostasis. 2006. 4:295-306. Marai I, et al. Anticardiolipin and anti-beta-2-glycoprotein I antibodies. Autoimmunity. 2005. 38(1):33-38. Atsumi T, et al. Research around beta 2-glycoprotein I: a major target for antiphospholipid antibodies. Autoimmunity. 2005. 38(5):377-381. Guidelines on the investigation and management of The Antiphospholipid Syndrome. British Journal of Haematology. 2000. 109:704-715. [Ref 2]

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