To evaluate the diagnostic properties of combined tests of anti cyclic citrullinated peptide antibody (anti-CCP) and rheumatoid factor (RF) in the diagnosis of rheumatoid arthritis (RA).
We performed an extensive research between January 2000 and January 2013 of the published literature. A random-effects model was used to summarise data from 24 studies that conformed to our inclusion criteria. Heterogeneity among studies was evaluated by threshold effect analysis and meta-regression.
The summary estimates for anti-CCP antibody and RF positivity (both serum markers had to be positive) in the diagnosis of RA were: sensitivity 57% (95% confidence interval (CI), 55% to 59%), specificity 96% (CI, 96% to 97%), positive likelihood ratio (LR) 13.84 (CI, 10.56 to 18.12), negative LR 0.46 (CI, 0.40 to 0.52), diagnostic odds ratio (DOR) 33.02 (CI, 23.89 to 45.64). The pooled data for anti-CCP antibody or RF positivity (one serum marker had to be positive) were: sensitivity 78% (CI, 76% to 80%), specificity 82% (CI, 81% to 84%), positive LR 4.24 (CI, 3.61 to 4.97), negative LR 0.27 (CI, 0.22 to 0.34), DOR 16.95 (CI, 12.96 to 22.18).
Both anti-CCP antibody and RF positivity are useful for ruling in the diagnosis of RA, and positivity combined improves the probability of true positivity in the diagnosis. Anti-CCP antibody or RF positivity shows low specificity and positive LR, and should be integrated with other examinations to make a final diagnosis.