Figure 2 Diagnostic value of the anti‐cyclic citrullinated peptide antibodies (anti‐CCP Ab) and rheumatoid factor (RF) for discriminating between rheumatoid arthritis and hepatitis C virus associated arthropathy, assessed by the area under the receiver operating characteristic curve (AUC): anti‐CCP (bold line), AUC = 0.94 (95% confidence interval, 0.87 to 0.98); RF (dotted line), AUC = 0.55 (0.45 to 0.65) (p<10⁻³).