Table 2.

Definitions of definite and probable CAPS.

	Criteria
Definite CAPS (All four criteria present)	1. Evidence of involvement of three or more organs, systems, and/or tissues
	2. Development of manifestations simultaneously or in less than a week
	3. Histopathological confirmation of small vessel occlusion in ≥1 organ/tissue
	4. Laboratory confirmation of the presence of antiphospholipid antibodies ≥12 weeks
Probable CAPS (One of the following)	All four criteria, but only two organs, systems, and/or sites of tissue involvement
	All four criteria, except for the laboratory confirmation at least 6 weeks apart due to the early death of a patient never tested for aPL before catastrophic APS
	Criteria 1, 2, and 4 above
	1, 3, and 4, and the development of a third event in more than a week but less than a month, despite anticoagulation

CAPS: catastrophic antiphospholipid syndrome; antiphospholipid antibodies (aPL): lupus anticoagulant, anticardiolipin antibodies, and/or anti-beta-2 glycoprotein 1. Adapted from [12].