CRP and rheumatoid arthritis: Traditional serological markers, such as C-reactive protein (CRP),[3] erythrocyte sediment rate (ESR),[4] Calprotectin,[5] rheumatoid factor (RF),[6] and anti-cyclic citrullinated peptide antibody (anti-CCP),[7] is commonly included as a surrogate marker of disease activity or applied as a valuable diagnostic biomarker in RA.