Table 2.

Preliminary classification criteria for catastrophic antiphospholipid syndrome [Asherson et al. 2003].

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. Confirmation by histopathology of small-vessel occlusion*

4. Laboratory confirmation of the presence of antiphospholipid antibodies†

Definite catastrophic antiphospholipid syndrome

• All four criteria present

Probable catastrophic antiphospholipid syndrome

• All four criteria, except only two organs, systems, and/or tissues involved

• All four criteria, except for the absence of laboratory confirmation of antiphospholipid antibodies

• Criteria 1, 2, and 4

• Criteria 1, 3, and 4, with the development of a third event more than 1 week but within 1 month of presentation, despite anticoagulation

^*Vasculitis may coexist, but significant thrombosis must be present as well.

^†“Positive aPL” twice 12 weeks apart (of note, the original Sapporo APS classification criteria required two positive aPL tests 6 weeks apart [Wilson et al. 1999], which has been changed to 12 weeks as part of the updated Sapporo APS classification criteria [Miyakis et al. 2006].