Anti-phospholipid antibody syndrome (APS, APAS, anti-cardiolipin syndrome, Hughes syndrome) is an autoimmune disease, which includes clinical symptoms such as arterial and venous thrombosis, thrombocytopenia and recurrent fetal loss. Primary and secondary forms of APAS can be distinguished. In the primary form of APAS, antibodies against phospholipids are formed without any underlying disease presence. In the secondary form of APAS, the symptoms are associated with other autoimmune diseases, particularly systemic lupus erythematosus (SLE).
Traditionally, laboratory diagnosis of APAS has been based on the study of antibodies against cardiolipin and ß2-glycoprotein I. Where these tests give a negative result, the determination of other antibodies provides an alternative diagnosis method. In addition, specific antibody profiles are associated with clinical complications associated with APAS, and may allow the differentiation between asymptomatic antibody carriers.