Diagnostic Value of Anti-CCP in Patients with Rheumatoid Arthritis Based on American College of Rheumatology Criteria

Rheumatoid arthritis (RA) is a chronic inflammatory arthritis specified by some antibodies. Although the most relevant antibody is rheumatoid factor (RF), it has little sensitivity and specificity for diagnosis of RA. Other groups of antibodies that are produced against the citrullinated epitopes have been proved to be more specific for diagnosing RA. Anti-CCP testing based on ELISA assay is the most effective test for detecting anti-filaggrin antibodies. Positive values of anti-CCP antibody a few years before the clinical signs and symptoms of RA along with high concentrations of this antibody in the synovial fluid increase the probability of citrollination in the pathogenesis of the disease. A combination of anti-CCP and RF would increase the sensitivity of both tests. Most previous studies have used RF as a gold standard for evaluating the diagnostic value of anti-CCP. However, RF is known to have a low sensitivity and specificity. Therefore, we decided to realistically evaluate the diagnostic value of anti-CCP based on American college of rheumatology (ACR) criteria as a gold standard. This was a descriptive study to evaluate the diagnostic value on 49 RA patients and 49 individuals with other rheumatic diseases. Blood samples were taken to measure erythrocyte sedimentation rate (ESR), RF, anti-CCP. Disease activity was then determined by DAS28. Data analysis was performed by 2 × 2 tables, chi-square test and receiver operating characteristic (ROC) curve for trade-off points. We used SPSS15. Data analysis showed anti-CCP to have a sensitivity of 71%, a specificity of 80%, a positive predictive value of 78%, a negative predictive value of 74%, a positive likelihood ratio of 3.55 and a negative likelihood ratio of 0.36. In this study, anti-CCP and RF had a statistically significant correlation (P < 0.001). Anti-CCP is a test with a high predictive value for diagnosing RA.