Determination of Specificity and Sensitivity of Rheumatoid Factor and Anti CCP Tests in Patients with RA in Private Clinic in Tehran, Iran

Rheumatoid Arthritis (RA) is a systemic, chronic, inflammatory and autoimmune disease that often leads to joint destruction. RA is the most common inflammatory joint disease of the world. The diagnosis of this disease has been based primarily on clinical manifestation. However the highly variable and unpredictable course of the disease suggests the need for highly sensitive and specific diagnostic tests that help to early diagnosis and treatment. We conducted a study to evaluate the sensitivity and specificity of Anti CCP and Rheumatoid Factor (RF) in our patients with RA. In this study we review documents of our patients with diagnosis of RA or other inflammatory diseases or healthy persons with simultaneous RF and Anti CCP tests. These patients visited in outpatient clinic or admitted in Imam Reza Hospital. Sensitivity and specificity of the tests were evaluated taking the clinical diagnosis as the gold standard. Our total cases were 833. 429 (51.5%) patients with RA and 404 (48.5%) non RA patients or normal population with RF and Anti-CCP test selected. There were 113 males and 316 females in RA patients and 27 males and 377 females in non RA group. Average of age in RA patents was 80 (5-88) and in non RA group was 78 (10-88). Base on statistical analysis in our patients the test sensitivity for RF and Anti CCP were 84.8% and 74.3%, respectively. Specificity for RF and Anti CCP were 72.5% and 92.8%, respectively. High specificity in the Anti CCP test support the diagnosis of RA. Anti CCP can be proved to be a powerful diagnostic tool especially in ambiguous cases or RF negative patients with RA. Key word: Rheumatoid Factor, Anti-CCP tests, specificity and sensitivity.