Rheumatoid Factor (RF), serum level

Short Name: RF
Sample required: Serum
Result Time: 2 HR

Rheumatoid factor (RF) is an autoantibody directed against the Fc portion of IgG, which is itself an antibody. It is present in about 70% of patients with rheumatoid arthritis. RF, often in low titers, occurs in patients with other diseases, including other connective tissue diseases (eg, SLE), granulomatous diseases, chronic infections (eg, viral hepatitis, subacute bacterial endocarditis, TB), and cancers. Low RF titers can also occur in 3% of the general population and 20% of the elderly. The rheumatoid factor (RF) test is primarily used to help diagnose rheumatoid arthritis and to distinguish it from other forms of arthritis and other conditions that cause similar symptoms of joint pain, inflammation, swelling, and stiffness. See Cyclic Citrullinated Peptide Antibodies, Serum