Test performance in systemic sclerosis: anti-centromere and anti-Scl-70 antibodies.

Abstract

PURPOSE:

To determine the sensitivity and specificity of anti-centromere (ACA) and anti-Scl-70 antibodies in systemic sclerosis (SSc).

METHODS:

Four-hundred ninety-seven English language articles published from 1966 to 1994 were identified by structured MEDLINE search. Articles in 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 and specificity from each study was converted into a 2 x 2 table, and combined across studies to calculate summary rates for each antibody. Author's clinical classification criteria for SSc served as the gold standard for disease diagnosis.

RESULTS:

In 30 articles that fulfilled inclusion criteria, ACA were found in 441 of 1,379 SSc patients (sensitivity 32%, range 17% to 56%). This increased to 57% (332 of 585) in patients with the limited cutaneous, or CREST, subset of SSc (IcSSc). Anti-Scl-70 antibodies were found in 366 of 1,074 SSc patients (sensitivity 34%, range 3% to 75%), and this increased slightly to 40% in patients with the diffuse cutaneous form of SSc (dcSSc). Both antibodies were 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. ACA 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 individual diagnostic tests in SSc, both ACA and anti-Scl-70 antibodies are 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 being specific in the detection of disease, but 40% of SSc patients are likely to have neither antibody present, and a negative result does not exclude the diagnosis. Measurement of these antibodies should be considered secondary to the clinical features when making a diagnosis of SSc.

• Authors: G Spencer-Green, D Alter, H G Welch
• Journal: The American journal of medicine (Am J Med) Vol. 103 Issue 3 Pg. 242-8 (Sep 1997) ISSN: 0002-9343 [Print] United States
• PMID: 9316557 (Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Review)

Chemical References

• Antibodies, Antinuclear
• Autoantibodies

Topics

• Antibodies, Antinuclear (blood)
• Autoantibodies (blood)
• Centromere (immunology)
• Diagnosis, Differential
• Humans
• Scleroderma, Systemic (diagnosis, immunology)
• Sensitivity and Specificity