Rheumatoid Factors and Antibodies to Citrullinated Proteins in the Laboratory Diagnosis of Rheumatoid Arthritis

Abstract

This study investigated the clinical significance of IgM and IgA rheumatoid factors (RF) and antibodies to citrullinated proteins (CCP, MCV, AKA) in rheumatoid arthritis (RA). 993 RA patients were compared to 616 controls. MCV showed the highest diagnostic sensitivity (83%), while CCP demonstrated the highest specificity (87%). CCP had the highest positive likelihood ratio (5.5). IgA RF and MCV exhibited the largest area under the curve (0.9) in ROC analysis. IgM RF levels correlated with joint damage and systemic manifestations, while CCP concentration correlated with disease activity. CCP and MCV demonstrated the best diagnostic efficacy for RA, with autoantibody levels correlating with disease severity and activity.