Validation of the Sapporo criteria for antiphospholipid syndrome.

OBJECTIVE

To test the Sapporo criteria for the classification of the antiphospholipid syndrome (APS).

METHODS

We classified 243 consecutive patients who had clinical diagnoses of primary APS (n = 49), secondary APS (n = 26), systemic lupus erythematosus (SLE) without clinical APS (n = 131), and lupus-like disease without clinical APS (n = 37).

RESULTS

Sensitivity, specificity, positive predictive value, and negative predictive value were 0.71, 0.98, 0.95, and 0.88, respectively. False-negative findings were the result of patients being classified on the basis of minor criteria that were not included in the Sapporo criteria, such as livedo reticularis, thrombocytopenia, low-titer IgG or IgM anticardiolipin antibody, IgA anticardiolipin antibody, and anti-beta2-glycoprotein I antibody. Some patients with false-negative results were true seronegative cases.

CONCLUSION

The Sapporo criteria for APS compare favorably with the American College of Rheumatology criteria for SLE and are usable for clinical studies.