Diagnostic criteria for APS

Clinical and laboratory criteria for antiphospholipid syndrome

At least one clinical and one laboratory criterion must be met:

  1. Thrombosis
    • ≥ 1 episodes of arterial, venous or small vessel thrombosis [1], OR

  2. Pregnancy morbidity
    • ≥ 1 unexplained deaths of a morphologically-normal fetus at or beyond week 10 of gestation, OR

    • ≥ 1 pre-term births of a morphologically normal neonate before week 34 of gestation because of: (i) eclampsia or severe pre-eclampsia, OR (ii) recognized features of placental insufficiency [2], OR

    • ≥ 3 unexplained consecutive spontaneous miscarriages before week 10 of gestation, provided maternal anatomic or hormonal abnormalities and paternal and maternal chromosomal causes are excluded

  1. Lupus anticoagulant present in plasma, on ≥ 2 occasions ≥ 12 weeks apart, OR
  2. Anticardiolipin antibody of IgG and/or IgM isotype in serum or plasma, present in medium or high titre (> 40GPL units or MPL units, or > the 99th centile), on ≥ 2 occasions, ≥ 12 weeks apart, OR
  3. Anti-b2–glycoprotein I antibody of IgG and/or IgM isotype in serum or plasma (titre > 99th centile), present on ≥ 2 occasions ≥ 12 weeks apart

These consensus criteria for the diagnosis of antiphospholipid syndrome (APS; also referred to as Hughes syndrome) were published in 2006 (1)

The consensus statement also includes specific definitions for antiphospholipid antibody-associated heart valve disease, livedo reticularis, thrombocytopenia and nephropathy, and recognizes that a other clinical and laboratory findings may also be associated with APS, including neurological manifestations, IgA anticardiolipin antibodies, IgA anti-b2GPI, antiphosphatidylserine antibodies, antiphosphatidylethanolamine antibodies, antiprothrombin antibodies against, and antibodies to the phosphatidylserine–prothrombin complex.1

Consensus guidelines for the classification and management of catastrophic antiphospholipid syndrome (APS) were published separately in 2003.2