Antiphospholipid antibodies in practice

Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by the occurrence of thrombotic or obstetrical events associated with the presence in the serum of patients of antibodies that are associated with thrombosis. For the diagnosis of APS, the presence of either lupus anticoagulant, anticardiolipin or anti-β2-glycoprotein1 antibodies of IgG or IgM isotype is required through laboratory testing. Other autoantibodies such as antiphosphatidylethanolamin or antiphosphatidylserin/prothrombin complex antibodies may be interesting in the diagnosis of APS when common antiphospholipid antibodies are missing. These autoantibodies are still under evaluation for their diagnostic contribution. Despite numerous attempts, the assays that are available for the identification of antiphospholipid antibodies have not been standardized yet, which leads to high variability between reagents and laboratories. Thus, to optimize the biological monitoring of APS syndromes, it is mandatory to have consecutive samples analyzed in the same laboratory.