Antiphospholipid syndrome (APS) is an autoimmune condition characterized by thrombosis (arterial, venous, and microvascular) and/or pregnancy morbidity occurring in subjects persistently positive for antiphospholipid antibodies (aPL). Current laboratory classification criteria for APS include the presence of lupus anticoagulant (LA), anticardiolipin (aCL), or anti-β2-glycoprotein I antibodies (aß2GPI) tested positive on two separate occasions at least 12 weeks apart [1]. While the APS classification criteria are being currently updated to improve homogeneity in clinical research [2], patients who seek medical treatment often have a variety of laboratory and/or clinical characteristics that may not completely encompass the classification criteria for overt APS.
