How is antiphospholipid syndrome (APS) defined?

By William Aird

According to the British Committee for Standards in Haematology Guidelines:

Antiphospholipid syndrome is diagnosed in a patient with thrombosis and/or defined pregnancy morbidity
who has persistent antiphospholipid antibodies (aPL). Venous thrombosis in APS is most commonly lower limb deep vein thrombosis (DVT) and/or pulmonary embolism (PE) but any part of the venous system may be involved, including superficial, portal, renal, mesenteric and intracranial veins.