Fig. 4

ROC curves comparing the diagnostic performance of rheumatoid factor (RF), antinuclear antibody (ANA), and anti-cyclic citrullinated peptide (ANTI-CCP) for RA. The ANTI-CCP test (green line) exhibits the highest AUC of 0.965 with a sensitivity of 78% and specificity of 90%, followed by the RF test (blue line) with an AUC of 0.849, sensitivity of 65%, and specificity of 100%. The ANA test (red line) shows an AUC of 0.721 with a sensitivity of 40% and specificity of 100%. These curves indicate that ANTI-CCP is the most effective marker for RA diagnosis, followed by RF and ANA.