CRP and rheumatoid arthritis: RA females patients with high and moderate disease activity as measured by DAS28-CRP had significantly elevated [median and IQR] IL-6 serum levels—15.2 [9.4–36.7] pg/ml for high activity group and 12.7 [3.3–43.4] pg/ml for moderate activity group as opposed to those with low activity: 1.52 [0.0–12.1] pg/ml; p = 0.007, Kruskal–Wallis test.