Diagnostic criteria for APS

Clinical and laboratory criteria for antiphospholipid syndrome

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

CategoryCriteria
Clinical
  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

Laboratory
  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