A positive rheumatoid factor test result indicates that a high level of rheumatoid factor was detected in your blood. A higher level of rheumatoid factor in your blood is closely associated with autoimmune disease, particularly rheumatoid arthritis. But a number of other diseases and conditions can raise rheumatoid factor levels, including:

  • Cancer
  • Chronic infections
  • Inflammatory lung diseases, such as sarcoidosis
  • Mixed connective tissue disease
  • Sjogren's syndrome
  • Systemic lupus erythematosus

Some healthy people — particularly older individuals — have positive rheumatoid factor tests, though it's not clear why. And some people who have rheumatoid arthritis will have low levels of rheumatoid factor in their blood.

May 21, 2016
  1. Firestein GS, et al. Autoantibodies in rheumatoid arthritis. In: Kelley's Textbook of Rheumatology. 9th ed. Philadelphia, Pa.: Saunders Elsevier; 2013. Accessed May 5, 2016.
  2. Rheumatoid factor. Lab Tests Online. American Association for Clinical Chemistry. Accessed May 5, 2016.
  3. Shmerling RH. Origin and utility of measurement of rheumatoid factor. Accessed May 5, 2016.
  4. Ferri FF. Rheumatoid arthritis. In: Ferri's Clinical Advisor 2016. Philadelphia, Pa.: Mosby Elsevier; 2016. Accessed May 5, 2016.

Rheumatoid factor