Anti-phospholipid syndrome (APS), also called Hughes syndrome, is an autoimmune disease which is characterised by thrombophilia. Cumulative haematological signs are mainly venous (37%) or arterial (27-49%) thrombosis, haemocytopenia (30-38%), pregnancy complications (55-74%), neurological failures (66%) and cardiological (27%), pulmonary (20-30%) or cutaneous (40%) tissue damage due to the above-mentioned circulatory disorders. APS is divided into primary APS (pAPS) and secondary APS (sAPS). These are characterised by the same haematological immune responses. In sAPS, however, they occur during the course of the disease as secondary reactions, most frequently in connection with rheumatic diseases (e.g. SLE). Anti-β2-GP1 antibodies are a highly specific marker for pAPS and sAPS, the latter of which is frequently associated with collagenosis. According to the "International consensus statement on an update of the classification criteria for definite antiphospholipid syndrome (APS) 2006“ the serological detection of β2-GP1 antibodies (strongest APS association of all detectable APS antibodies) is indicated as a serological criterion in APS diagnostics. The determination of anti-β2-GP1 antibodies is indispensable in suspected cases of APS that are negative for antibodies against cardiolipin or lupus anticoagulans. This is generally the case in 3%-14% of APS patients. Furthermore, anti-β2-GP1 antibodies are a biological marker for APS-induced pregnancy complications with a prevalence of approx. 6%.