Rheumatoid Factor (RA Factor): what your level actually means
Also known as: RF, Rheumatoid Factor Test · Updated 19 Aug 2026 · Educational — not medical advice
The short answer: Rheumatoid factor is generally considered negative below about 14 IU/mL, but a positive result does not mean a person has rheumatoid arthritis — roughly a small percentage of healthy people test positive with no joint disease at all, and the rate climbs further with age. It's more useful as one piece of a larger picture that includes joint symptoms, examination findings, and other blood tests like anti-CCP antibodies, rather than as a stand-alone diagnostic test.
Where does your value sit?
This Rheumatoid Factor (RA Factor) value is inside the normal range. Your lab's printed reference range takes precedence — ranges vary slightly between laboratories.
What Rheumatoid tells you
Rheumatoid factor is an antibody that mistakenly targets other antibodies in the blood, and it's found in many people with rheumatoid arthritis, though not all. It's also seen with several other autoimmune and infectious conditions and even in some healthy people, which limits how much a positive result alone can tell you without the full clinical picture. (Illustration is schematic.)
Common reasons it rises
- Rheumatoid arthritis — the condition this test is most associated with, though it's positive in only a majority, not all, cases.
- Other autoimmune conditions — Sjögren's syndrome, lupus, and similar conditions can also raise rheumatoid factor.
- Chronic infections — including some viral and bacterial infections, can cause a positive result.
- Aging — the likelihood of a positive rheumatoid factor without any disease increases somewhat with age.
- Other inflammatory conditions — certain chronic inflammatory states outside the joints can also raise it.
And reasons it runs low
- A negative rheumatoid factor does not rule out rheumatoid arthritis, since a meaningful portion of people with the disease never test positive for this antibody.
Does food or exercise change this?
Check with your doctor first: Anyone with joint pain, swelling, or stiffness alongside this result should be evaluated by a doctor rather than relying on diet or exercise changes alone.
General guidance for adults — not a personal diet plan. Your doctor or dietitian knows your full picture.
Checked against: Rheumatoid factor (RF) test (MedlinePlus) · Rheumatoid arthritis (Arthritis Foundation) · Rheumatoid arthritis (Mayo Clinic)
What to do next
Ask your doctor: “Given my joint symptoms, how much weight does this positive result actually carry?”
Ask your doctor: “Should an anti-CCP antibody test also be checked to get a clearer picture?”
Ask your doctor: “If this is negative but my symptoms continue, does that change how we proceed?”
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Questions people ask
Does a positive rheumatoid factor mean I have rheumatoid arthritis?
Not on its own. Rheumatoid factor can be positive in other autoimmune conditions, some infections, and even in healthy people, especially with increasing age. Doctors combine this result with joint symptoms, a physical exam, and often the more specific anti-CCP antibody test before considering a diagnosis.
Can someone have rheumatoid arthritis with a negative rheumatoid factor?
Yes, this pattern is common enough that it has its own name, seronegative rheumatoid arthritis. A negative result doesn't rule out the disease, which is why diagnosis relies on the overall clinical picture rather than this single blood test. Doctors weigh joint symptoms, imaging, and other antibody tests like anti-CCP just as carefully in these seronegative cases before reaching a diagnosis.
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