What Is A Rheumatoid Factor Test And How Is It Used To Diagnose Rheumatoid Arthritis?

Dr. Eric Ruderman answers the question: 'What Is A Rheumatoid Factor Test?'

ByABC News
November 19, 2008, 10:22 AM

— -- Question: What is a rheumatoid factor test and how is it used to diagnose rheumatoid arthritis?

Answer: Rheumatoid arthritis, like many of the things that we see in rheumatology, is an autoimmune disease in which the body's own immune system is working against itself. Rheumatoid factor is one manifestation of this, and rheumatoid factor is a measurement of antibodies that are actually directed against the body's own proteins.

We have found that this is associated with rheumatoid arthritis. It's not clear that it actually causes the disease or even worsens the disease, but we know that it's associated. And we also know that patients who have high levels of these rheumatoid factor antibodies are more likely to have severe disease and more likely to have destructive disease.

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