What are the clinical criteria for diagnosis of antiphospholipid syndrome (APS)?

Updated: Nov 24, 2020
  • Author: Suneel Movva, MD; Chief Editor: Herbert S Diamond, MD  more...
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The clinical criteria consist of vascular thrombosis and pregnancy morbidity. Vascular thrombosis is defined as one or more clinical episodes of arterial, venous, or small-vessel thrombosis in any tissue or organ confirmed by findings from imaging studies, Doppler studies, or histopathology.

Thrombosis may involve the cerebral vascular system, coronary arteries, pulmonary system (emboli or thromboses), arterial or venous system in the extremities, hepatic veins, renal veins, ocular arteries or veins, or adrenal glands. Investigation is warranted if a history of deep venous thrombosis (DVT, pulmonary embolism (PE), acute ischemia, myocardial infarction (MI), or stroke (especially when recurrent) is present in a younger individual (males < 55 y; females < 65 y) or in the absence of other risk factors.

Pregnancy morbidity is defined as the following:

  • One or more late-term (>10 weeks' gestation) spontaneous abortions

  • One or more premature births of a morphologically healthy neonate at or before 34 weeks’ gestation because of severe preeclampsia or eclampsia or severe placental insufficiency

  • Three or more unexplained, consecutive, spontaneous abortions before 10 weeks’ gestation

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