The mean PCT were significantly higher in patients with RA (6.90 ± 11.81 × 10−3 ng/mL) compared with healthy controls (1.70 ± 6.12 × 10−3 ng/mL) (p < 0.001) and the difference remained statistically significant after adjusting for age and sex. Here, CALCA is linked to rheumatoid arthritis.