The sensitivity, specificity and accuracy of anti-citrulline antibody test in diagnosis of rheumatoid arthritis

Citrulline antibody, nowadays, is a new item which has been the center of attention due to its much more specificity to diagnose RA. The aim of the present study was to evaluate the efficacy and accuracy of anti-citrulline antibody test in RA diagnosis among hospitalized patients in Iran. Through a case-control study, we tried to calculate the accuracy of anti-cyclic citrullinated peptide antibody (anti-CCP) test used in the diagnosis of RA enrolling 200 participants divided into two groups of the patients with RA, on the one hand, and other diseases, on the other. Anti-CCP was measured by ELISA technique through which titers more than 15 were defined as high titer. Of all the studied population, 81 (81 %) were in active phase of RA, which had anti-CCP > 15 U/ml, while only 25 controls (25 %) experienced these levels. The average anti-CCP was 144 U/ml in cases and 16.05 U/ml in controls with a P value < 0.001, which confirmed significant difference between the two. Considering different comments on this matter besides our findings in the present research, we offer a combination of anti-citrulline antibody test rather than anti-CCP and RF to get the best results in RA diagnosis, discrimination and prognosis because of 97 % specificity.