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:
- Chronic infections
- Inflammatory lung diseases, such as sarcoidosis
- Mixed connective tissue disease
- Sjogren's syndrome
- Systemic lupus erythematosus
Some healthy people 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.
July 09, 2013
- Firestein GS, et al. Kelley's Textbook of Rheumatology. 9th ed. Philadelphia, Pa.: Saunders Elsevier; 2013. http://www.mdconsult.com/das/book/body/208746819-6/0/1807/0.html. Accessed April 4, 2013.
- Rheumatoid factor. Lab Tests Online. http://labtestsonline.org/understanding/analytes/rheumatoid/tab/glance. Accessed April 4, 2013.
- Shmerling RH. Origin and utility of measurement of rheumatoid factors. http://www.uptodate.com/home. Accessed April 4, 2013.
- Ferri FF. Ferri's Clinical Advisor 2013: 5 Books in 1. Philadelphia, Pa.: Mosby Elsevier; 2012. http://www.mdconsult.com/books/about.do?eid=4-u1.0-B978-0-323-08373-7..00002-9&isbn=978-0-323-08373-7&about=true&uniqId=343863096-23. Accessed April 4, 2013.