(Fig. 1a and Table 1) Serum CTGF had high diagnostic value for RA in terms of sensitivity, specificity, and the AUC, which were 0.86, 0.92, and 0.92, respectively, at the cutoff value of 88.66 pg/mL (Youden’s index, 0.78; Fig. 1b). This evidence concerns the gene CCN2 and rheumatoid arthritis.