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Rheumatoid Factor (RF) - description and reference ranges

What is it?

Rheumatoid factors (RF) are proteins produced by your immune system. Rheumatoid factors are antibodies that can attack healthy cells and tissues by mistake if you have an autoimmune disorder and a lot of the RFs in the body. Having RFs in your blood does not necessarily mean that you have a problem, but generally it does point to an autoimmune disorder or other conditions. However, a standalone RF result cannot diagnose any specific conditions, it needs to be looked at together with your health history and symptoms.

Reference ranges

If your indicative RF concentration is lower than the reference range for our laboratory:

Generally this implies that you do not have RF antibodies and an autoimmune condition. It does not, however, rule out rheumatoid arthritis. It is possible to have rheumatoid arthritis and no rheumatoid factor antibodies. If you have symptoms, they should be investigated further.

You can discuss this result with your GP.

If your indicative RF concentration is higher than the reference range for our laboratory:

The higher your RF test results, the more likely it is that you have a condition linked to rheumatoid factors. You may have an autoimmune disorder or rheumatoid arthritis. A chronic infection is also a possibility.

You can discuss this result with your GP.

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