Present in 80% of patients with rheumatoid arthritis but can be seen in bacterial endocarditis, cryoglobulinemia, Sjogren’s syndrome, SLE and postviral arthropathies.
An autoantibody defined as an antibody against the Fc portion of IgG.
RF and IgG join to form immune complexes that contribute to the disease process.
Titers correlate with severity of rheumatoid arthritis and the likelihood of extra-articular manifestations.
Can also be a cryoglobulin, either type 2 or type 3 (polyclonal IgM to polyclonal IgG) cryoglobulin.
Part of the disease criteria of rheumatoid arthritis.
Its presence can also indicate the occurrence of suspected autoimmune activity unrelated to rheumatoid arthritis.
High levels of rheumatoid factor occur in rheumatoid arthritis and Sjögren’s syndrome.
Seen in 80% of cases of rheumatoid arthritis and 70% of cases of Sjögren’s syndrome.
May be present in 5-10% of healthy persons, especially the elderly.
Present in many acute and chronic inflammatory disease, as well as in a small percentage of healthy individuals.
Associated with more persistent synovitis, more joint damage and disability.
Rheumatoid factor may also be elevated in: chronic hepatitis, primary biliary cirrhosis, any chronic viral infection, bacterial endocarditis, leukemia, dermatomyositis, infectious mononucleosis, systemic sclerosis, and systemic lupus erythematosus, Epstein-Barr virus and Prvovirus infection.