Table 1.

Updated antiphospholipid syndrome classification criteria [Miyakis et al. 2006].

Clinical criteria 1. Vascular thrombosis:   ≥ 1 clinical episodes of arterial, venous, or small vessel thrombosis, in any tissue or organ 2. Pregnancy morbidity:   (a) ≥ 1 unexplained deaths of a morphologically normal fetus at or beyond the 10th week of gestation, or   (b) ≥ 1 premature births of a morphologically normal neonate before the 34th week of gestation because of: eclampsia, severe preeclampsia, or recognized features of placental insufficiency, or   (c) ≥ 3 unexplained consecutive spontaneous abortions before the 10th week of gestation, with maternal anatomic or hormonal abnormalities and paternal and maternal chromosomal causes excluded.

Laboratory criteria 1. Lupus anticoagulant present in plasma, on ≥ 2 occasions at least 12 weeks apart 2. Anticardiolipin antibody of IgG and/or IgM isotype, in medium or high titer (>40 GPL or MPL, or > the 99th percentile), on ≥ 2 occasions, at least 12 weeks apart. 3. Anti-β2-glycoprotein-I antibody of IgG and/or IgM isotype, in medium or high titer (> the 99th percentile), on ≥ 2 occasions, at least 12 weeks apart.

Definite APS is present if at least one of the clinical criteria and one of the laboratory criteria are met.