Task force report on “criteria” antiphospholipid antibody tests

Abstract

A Task Force of experts in the Antiphospholipid Syndrome (APS) field met prior to the 13th International Congress on Antiphospholipid Antibodies and addressed a number of critical questions regarding the antiphospholipid antibody (aPL) tests included in current international consensus criteria for the classification of APS (anticardiolipin antibodies (aCL), anti-β2glycoprotein I antibodies (aβ2GPI), and lupus anticoagulant (LA) test, namely, the “criteria” aPL tests). The Task Force was divided into the following three subgroups: (1) aCL and aβ2GPI tests, (2) LA test, and (3) the role of aPL as thrombotic risk factors. Subgroup 1 reviewed and critiqued the current state of aCL/aβ2GPI testing and recommended developing international consensus guidelines for performance of these assays and establishing universal units of measurement for anti-β2GPI. Subgroup 2 reviewed recent guidelines for LA testing published by the International Society of Thrombosis and Haemostasis Standardization Subcommittee (ISTH-SSC) on Lupus Anticoagulants and Phospholipid-dependent Antibodies; the subgroup recommended continued close collaboration with ISTH-SSC to address remaining issues, including the role of TCT and PT in LA testing and the validity of integrated test systems that lack mixing studies. Subgroup 3 emphasized the need for more data on the risks associated with aPL and recommended collaborative studies using existing large, population-based, prospective cohorts with available data on thrombosis and/or pregnancy outcomes. Such studies should include a comprehensive panel of current and newer aPL assays, assess the effect of antibody titer, analyze the risks associated with combinations of aPL, and use state-of-the-art statistical approaches for assessment of risk factors.