The role of Rheumatoid Factor and Anti-Cyclic Citrullinated Peptide Antibody in Diagnosis of Rheumatoid Arthritis

Background: Rheumatoid Factor (RF) occurs in 70- 90% of patients with established rheumatoid arthritis (RA). Anti-cyclic citrullinated peptide antibody (Anti-CCP) detection may be used to confirm the diagnosis of RA in patients with uncharacterized chronic inflammatory arthritis. This study is an attempt to evaluate the role of RF and anti-CCP in the diagnosis and prognosis of rheumatoid arthritis. Methods: Blood samples were obtained from 55 patients with established RA and 55 healthy controls. Anti-CCP and RF were measured by ELISA and nephelometry. The patient's demographics, disease duration, DMARDs usage, ESR and radiographic abnormalities were recorded. Results: Fifty five RA patients and 55 healthy age and sex matched controls were enrolled. Odd ratio (OR) was 87.42 (CI=11.2-680.1) for RF and 27.48 (6/08-124/09) for Anti- CCP. Five patients had used more than 3 DMARDs; all of them were RF positive and 4 were also anti-CCP positive. Eleven patients had erosions in their radiographs; 10 of them were seropositive for RF and 9 positive for anti-CCP. Conclusion: Our study suggests that despite lack of specificity, RF continues to be a central part of the definition of RA due to favorable sensitivity profile and the combined use of RF. Also, anti-CCP is a more powerful diagnostic and prognostic tool.