TEST-PERFORMANCE IN SYSTEMIC-SCLEROSIS - ANTICENTROMERE AND ANTI-SCL-70 ANTIBODIES

PURPOSE: TO determine the sensitivity and specificity of anti-centrome re (ACA) and anti-Scl-70 antibodies in systemic sclerosis (SSc). METHO DS: Four-hundred ninety-seven English language articles published from 1966 to 1994 were identified by structured MEDLINE search. Articles i n which either ACA or anti-Scl-70 antibodies were measured in both SSc patients and a non-SSc control group were reviewed and rated using a previously published diagnostic testing scale. Reported sensitivity an d specificity from each study was converted into a 2 x 2 table, and co mbined across studies to calculate summary rates for each antibody. Au thor's clinical classification criteria for SSc served as the gold sta ndard for disease diagnosis. RESULTS: In 30 articles that fulfilled in clusion criteria, ACA were found in 441 of 1,379 SSc patients (sensiti vity 32%, range 17% to 56%). This increased to 57% (332 of 585) in pat ients with the limited cutaneous, or CREST, subset of SSc (lcSSc). Ant i-Scl-70 antibodies were found in 366 of 1,074 SSc patients (sensitivi ty 34%, range 3% to 75%), and this increased slightly to 40% in patien ts with the diffuse cutaneous form of SSc (dcSSc). Both antibodies wer e measured in 670 patients, and either test was positive in 58% (range 29% to 86%), but in only 3 patients were both antibodies present. The specificity of each antibody was high, but varied by control group. A CA were present in 5% and anti-Scl-70 antibodies were present in 2% of patients with other connective tissue diseases, but fewer than 1% of disease free controls had either antibody present. CONCLUSIONS: As ind ividual diagnostic tests in SSc, both ACA and anti-Scl-70 antibodies a re highly specific. Each performs somewhat better as discriminators of clinical subsets for patients in whom a diagnosis of SSc has already been established. Clinicians can rely on a positive test result as bei ng specific in the detection of disease, but 40% of SSc patients are l ikely to have neither antibody present, and a negative result does not exclude the diagnosis. Measurement of these antibodies should be cons idered secondary to the clinical features when making a diagnosis of S Sc. (C) 1997 by Excerpta Medica, Inc.