As shown in Figure 3, when early RA patients compared with all controls, the AUC of single indicators of RF and anti-RA33 was 0.60 and 0.65, respectively, while with the additions of PCT and CT, the diagnostic ability for early RA further improved with the AUC of 0.80 and 0.79, respectively (p < 0.05). The gene discussed is CALCA; the disease is rheumatoid arthritis.