The objective of this study was to assess the accuracy of diagnosing autoimmune disorders in the community and the effect of misdiagnosis on medical care. Previous studies suggested a reluctance on the part of primary care physicians to propose a tentative diagnosis,6,7,16 an interpretation supported by the present study in which 47 patients were excluded because the referring physician did not provide a tentative diagnosis. Final diagnoses were arrived at by consensus among a group of specialists using accepted diagnostic criteria.17,18 As all patients underwent complete reevaluation, bias introduced by knowing the referring physicians’ diagnoses was minimized. The low rate of agreement between the referring and final diagnosis supports that conclusion. Our results indicate that autoimmune diseases, especially SLE, are overdiagnosed by community physicians. The most frequent final diagnosis for those patients whose referring and final diagnosis differed was positive ANA. It is unlikely that these positive-ANA individuals had early SLE not yet meeting the diagnostic criteria, because they did not exhibit clinical manifestations regarded as highly specific for SLE19 (Figure, B). Overall, 137 patients received an incorrect diagnosis of SLE (positive predictive value, 51%). Most of these patients had a positive ANA finding as the sole criterion for SLE. The serological test results that were negative for disease-specific autoantibodies further supported the notion that most did not have early SLE. Autoimmune disease, which was rare among the positive-ANA subjects, frequently develops in individuals with anti-dsDNA or anti-Sm antibodies.15,20,21 In contrast, a positive ANA finding in the absence of physical signs and symptoms has limited diagnostic utility.22 Depending on age, 3% to 13% of healthy, asymptomatic people are seropositive for ANA.23- 25 Many other conditions are associated with a positive ANA test, including viral or bacterial infections, autoimmune thyroid disease, and medication use.23,26 There is little evidence that lupus eventually develops in these individuals.