The test measures the amount of rheumatoid factor in your blood.
Rheumatoid factor is an autoantibody produced by the immune system in people with rheumatoid arthritis.
High levels of RF in your blood indicate that you may have an autoimmune disease such as RA orSjogren’sdisease.
Verywell / Joshua Seong
However, not everyone who tests positive for RF has rheumatoid arthritis.
RF can also be found in a small percentage of healthy people, particularly aging individuals.
Sometimes it is ordered to support a diagnosis ofSjogren’sdisease, both of which are autoimmune diseases.
Get our printable guide for your next doctor’s appointment to help you ask the right questions.
All of the tests used to diagnose adult RA may also be ordered for a child with JRA symptoms.
How the Test Is Done
The RF test is a simple blood test.
A standard blood draw is a low-risk procedure that’s safe for most people.
Contact your insurer for more details if needed.
A test is considered positive, high, or elevated if the result is higher than normal.
Your RF test result, whether positive or negative, is just one piece of the diagnostic puzzle.
What happens if rheumatoid factor is positive?
A positive RF test result doesn’t mean you necessarily have rheumatoid arthritis or Sjogren’s disease.
Get our printable guide for your next doctor’s appointment to help you ask the right questions.
Some of them include:
What cancers have high rheumatoid factor?
The RF test is not used to diagnose cancer.
However, positive RF is sometimes found in people with blood cancers such as leukemia or multiple myeloma.
Some studies have also found that people with positive RF may be at an increased risk of developing cancer.
Summary
Rheumatoid factor is an autoantibody that forms in people who have rheumatoid arthritis.
The RF test is often used to help diagnose rheumatoid arthritis (RA).
Other health conditions can also cause RF to be elevated.
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