title: Validation of the Sapporo criteria for antiphospholipid syndrome.
abstract: 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.
  
  
  CONCLUSIONS
  The Sapporo criteria for APS compare favorably with the American College of Rheumatology criteria for SLE and are usable for clinical studies.
authors.affiliation: Hospital for Special Surgery, Weill/Cornell Medical College, New York, New York 10021, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Lockshin
authors.forename: L R
authors.initials: LR
authors.lastname: Sammaritano
authors.forename: S
authors.initials: S
authors.lastname: Schwartzman
mesh_terms: D000328:Adult; D000906:Antibodies / Q000097:blood; D017153:Antibodies, Anticardiolipin / Q000097:blood; D016736:Antiphospholipid Syndrome / Q000097:blood / Q000145:classification*; D005188:False Negative Reactions; D005260:Female; D006023:Glycoproteins / Q000276:immunology; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D015203:Reproducibility of Results; D017445:Skin Diseases, Vascular / Q000175:diagnosis; D013921:Thrombocytopenia / Q000175:diagnosis; D053482:beta 2-Glycoprotein I
chemical_list: D000906:Antibodies; D017153:Antibodies, Anticardiolipin; D006023:Glycoproteins; D053482:beta 2-Glycoprotein I