Overview and Clinical Significance

Rheumatoid factor (RF) is an autoantibody that targets the Fc portion of IgG antibodies, contributing to immune complex formation and inflammation. It is primarily associated with rheumatoid arthritis (RA) but can also be present in other autoimmune and infectious conditions.

Clinical Significance

• Rheumatoid Arthritis & Autoimmune Diseases: RF is detected in 70-80% of RA cases, aiding in diagnosis.
• Systemic Inflammation & Vasculitis: High RF levels correlate with vasculitis, neuropathy, and rheumatoid nodules.
• Other Autoimmune Conditions: RF may be elevated in Sjögren’s syndrome, lupus, and mixed connective tissue disease.
• Chronic Infections: RF can be detected in hepatitis C, tuberculosis, and infective endocarditis.
• Diagnostic Limitations: RF is not exclusive to RA, and 5-10% of healthy individuals, especially the elderly, may test positive.

RF testing is commonly used in rheumatology and immunology, helping assess autoimmune activity, inflammatory severity, and disease progression.
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