Skip to content
Missed Black Friday? Check out our HUGE offers for Christmas!
Missed Black Friday? Check out our HUGE offers for Christmas!

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.

Quick test finder

Quick test finder

Find what you need in under 30 seconds with our (very clever!) test finder. We offer a huge range of markers all a few clicks away, as well as fastest turnaround times.

Find your test

You might also like to read

  • The PSA Blood Test and Prostate Cancer Screening
    Adam Staten

    The PSA Blood Test and Prostate Cancer Screening

    In the UK, we screen for many different conditions. This starts before we are even born when foetuses are screened for conditions such as Down’s syndrome then, in the new born period, babies are screened for metabolic diseases and hearing problems, school children are screened for colour blindness, and in adulthood we are screened for breast cancer, cervical cancer, and bowel cancer. But we don’t screen for prostate cancer despite the existence of a simple blood test that can alert us to the possibility of the disease.

    Why not?

    Read now
  • Dr Mike Forsythe on Vitamin B12
    Dr Mike Forsythe

    Dr Mike Forsythe on Vitamin B12

    Vitamin B12, also known as cobalamin, is a unique nutrient, as it’s the only vitamin we require that must be sourced externally from animal-derived foods or supplements. So how do we know if we are getting enough of it? What...

    Read now