CRP and rheumatoid arthritis: Meanwhile, the diagnostic value was discovered for CRP, ESR and calprotectin in differentiating RA patients from HCs (CRP: AUC = 0.765, 95%CI:0.636–0.823; ESR: AUC = 0.708, 95%CI:0.624–0.802; calprotectin: AUC = 0.812, 95%CI: 0.692–0.870) (Table 4).