Comparison of Anti-Cyclic Citrullinated Peptide Antibodies Test with IgM- Rheumatoid Factor in the Diagnosis of Rheumatoid Arthritis
Rafidain Journal of Science,
2012, Volume 23, Issue 3, Pages 8-22
AbstractRheumatoid Factor (RF) occurs in 70- 90% of patients with established rheumatoid arthritis (RA). Anti-cyclic citrullinated peptide antibody (Anti-CCP) detection can be used to diagnose RA patients with uncharacterized chronic inflammatory arthritis. The aims of the study are: 1-To measure the serum levels of anti-CCP and IgM-RF in the RA patients and the control groups. 2-To evaluate and compare these diagnostic tests in the terms of sensitivity and specificity and to determine the test which yields the best combination of sensitivity and specificity in the diagnosis of RA. 3- To assess the relationship between anti-CCP antibodies test and joints deformities in comparison with IgM-RF antibodies test. Blood sample were obtained from 55 patients with established RA attending the Rheumatology Ward of Ibin-Sina Teaching Hospital during the period of 1st November 2010 to the 1st June 2011 and 35 apparently healthy controls. Anti-CCP antibodies and IgM-RF were measured using enzyme linked immunosorbent assay (ELISA). Patients demographic data, disease duration and joint deformities were recorded. The sensitivity and specificity of anti-CCP and IgM-RF antibodies were calculated taking the clinical diagnosis as the gold standard. Fifty five patients and 35 healthy age and sex matched controls were enrolled. Sensitivity was highest for IgM-RF test (58.18%) followed by anti-CCP test (56.3%). Specificity was highest for anti-CCP test (97.14%) followed by IgM-RF test (82.85%). A combination of the two tests improve the sensitivity and specificity for RA diagnosis to reach 59.5% and 100% respectively. Of the special diagnostic value was the detection of positive anti-CCP antibodies in 3/23 (11.5%) of IgM-RF negative patients. Furthermore, in RA patients with hand joints deformities, anti-CCP was more often presented. The same results were obtained for IgM-RF seropositivity. The study suggests that despite lack of specificity, IgM-RF continues to be a central part of the definition of RA due to favorable sensitivity profile. Anti-CCP test is a powerful diagnostic tool of high specificity especially in RF negative RA patients. No superiority of one test over the other regarding prognosis of joint deformity was discovered.
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