Abstract: Objective　To investigate the sensitivity and specificity of IgM-rheumatoid factor（RF），IgG-RF，IgA-RF and anti-cyclic citrullinated peptide（CCP） antibody by respective detection and combined detectionfor the diagnosis of rheumatoid arthritis（RA） and their diagnosis significance.   Methods　A total of 105 patients with RA，42 patients with other autoimmune diseases and 63 healthy subjects were enrolled. Serum IgM-RF，IgG-RF，IgA-RF and anti-CCP were detected by enzyme-linked immunosorbent assay（ELISA）. The results were analyzed statistically. Results　〖JP2〗The positive rates and concentrations of IgM-RF，IgG-RF，IgA-RF and anti-CCP in RA group were higher than those of other autoimmune disease group and healthy control group（P＜0.01）. The concentrations of IgA-RF in patients with disease activity score 28（DAS28）>5.1 were higher than those with 2.6＜DAS28≤5.1（P＜0.05）. The diagnostic sensitivities of IgM-RF，IgG-RF，IgA-RF and anti-CCP were 89.52%，36.19%，80.95% and 76.19%，respectively. The specificities of IgM-RF，IgG-RF，IgA-RF and anti-CCP were 82.86%，95.23%，89.52% and 99.05%，respectively. The sensitivity of combined detection of IgM-RF，IgG-RF，IgA-RF and anti-CCP was 92.38%，which was higher than those of IgA-RF detection（P＜0.05），IgG-RF detection（P＜0.01） and anti-CCP detection（P＜0.01），and its specificity was 100.00%，which was obviously higher than those of IgM-RF and IgA-RF detections（P＜0.01）. Conclusions　IgM-RF，IgG-RF，IgA-RF and anti-CCP are useful indices for the diagnosis of RA，and the combined detection of IgM-RF，IgG-RF，IgA-RF and anti-CCP can improve the sensitivity and specificity of diagnosis. IgA-RF may be an index for evaluating the activity of RA.

Key words: Rheumatoid factor, Anti-cyclic citrullinated peptide antibody, Rheumatoid arthritis