Classification Criteria for the Antiphospholipid Syndrome: Not the Same as Diagnostic Criteria for Antiphospholipid Syndrome

The latest consensus "guidelines" outlining revised Classification Criteria for antiphospholipid syndrome (APS) has just been published.[1] The aim of this publication was to develop new APS classification criteria with high specificity to be used in observational studies and trials, jointly supported by the American College of Rheumatology (ACR) and the European Alliance of Associations for Rheumatology (EULAR). Currently, classification of APS, for identification of homogeneous research cohorts, is based on the Sapporo criteria published in 1999,[2] as revised in Sydney in 2006.[3] The Sydney revised Sapporo criteria for APS require clinical features (thrombosis or pregnancy morbidity) and laboratory tests for antiphospholipid antibodies (aPL; i.e., lupus anticoagulant [LA], IgG/IgM anticardiolipin antibodies [aCL], and/or IgG/IgM anti-b2-glycoprotein I antibodies [aβ2GPI]), with a minimum of one positive aPL test, performed on two occasions at least 12-week apart.[3]