Serum levels of cartilage oligomeric matrix protein are elevated in rheumatoid arthritis, but not in inflammatory rheumatic diseases such as psoriatic arthritis, reactive arthritis, Raynaud's syndrome, scleroderma, systemic lupus erythematosus, vasculitis and Sjögren's syndrome

Progressive bone and cartilage destruction in arthritic joints leads to irreversible joint destruction and, subsequently, to functional declines and to work disability. During recent years a lot of interest has been focused on serum biomarkers in the clinic to evaluate the ongoing disease process in the cartilage and bone. New biomarkers such as osteoprotegerin or receptor activator of NF-κB ligand have been developed to describe the local bone process in affected joints.