Table 1.

Classification criteria for antiphospholipid syndrome

APS is present if one of the clinical criteria and one of the laboratory criteria are met.
Clinical criteria	Vascular thrombosis	≥1 clinical episode of arterial, venous, or small-vessel thrombosis
	Pregnancy morbidity	(a) ≥1 unexplained death of a morphologically normal fetus at ≥10 weeks of gestation (b) ≥1 premature delivery of a morphologically normal fetus at <34 weeks gestation because of:  (i) Severe preeclampsia or eclampsia defined according to standard definition (ii)  Recognized features of placental insufficiency (c) ≥3 unexplained consecutive miscarriages at <10 weeks gestation, with maternal and paternal factors (anatomic, hormonal or chromosomal abnormalities) excluded
Laboratory criteria	The presence of antiphospholipid antibodies on ≥2 occasions ≥12 weeks apart  (a) Presence of lupus anticoagulant in plasma  (b) Medium-to-high-titer anticardiolipin antibodies of IgG or IgM isoforms  (c) Medium-to-high-titer antibeta-2 glycoprotein-I (antiβ2GPI) antibodies of IgG or IgM isoforms

APS, antiphospholipid syndrome. Data from [2].