Fig. 3

Serum indicators and combinations of serum indicators for diagnosis of rheumatoid arthritis (RA). a Receiver operating characteristic (ROC) analysis of connective tissue growth factor (CTGF), anti-citrullinated protein antibodies (ACPA), and their combination for diagnosing RA. Serum ACPA concentrations were tested in all participants recruited to the validation cohort. ROC analysis was carried out, and the area under the curve (AUC) for CTGF and ACPA was 0.93 and 0.80, respectively. The combination of CTGF and ACPA further improved the diagnostic ability for RA with an AUC of 0.96. b ROC analysis for CTGF, RF, and their combination for diagnosing RA. Serum rheumatoid factor (RF) concentrations were tested for all participants recruited to the training cohort. ROC analysis was carried out, and the AUC for CTGF and RF, and for their combination, was 0.93, 0.8, and 0.95, respectively. c. ROC analysis of the combinations of ACPA and RF, and CTGF, ACPA, and RF for diagnosing RA. We tested the diagnostic value of the currently recommended serum assay, and the AUC for the combination of ACPA and RF was 0.86, while the AUC for adding CTGF to the combined ACPA and RF was significantly increased to 0.97