RA Factor (Rheumatoid Factor): normal range & what your result means
Written & medically reviewed by Dr. Sanjay Anbu, MBBS· Last reviewed
The rheumatoid factor (RA factor) test looks for an antibody often present in rheumatoid arthritis and some other conditions. It helps assess joint pain, but a positive result alone does not confirm arthritis.
A high RA factor supports (but does not prove) rheumatoid arthritis, especially with joint symptoms
It can also be raised in other autoimmune and chronic infections
Higher levels can suggest more active disease
What a LOW result can mean
A negative result does not fully rule out rheumatoid arthritis — some people have "seronegative" disease
The result is always read alongside symptoms and other tests such as anti-CCP and CRP
Ranges vary by lab. Reference ranges are TYPICAL ADULT values and vary by laboratory, age, sex, pregnancy and the method used. Always read your result against the range printed on YOUR report, and let your doctor interpret it alongside your history.
Frequently asked questions
Does a positive RA factor mean I have rheumatoid arthritis?
Not on its own. RA factor can be positive in healthy people and in other conditions. Doctors combine it with your symptoms, examination and tests like anti-CCP and CRP.
Can RA factor be negative in arthritis?
Yes. Some people with genuine rheumatoid arthritis are RA-factor negative (seronegative). This is why the test is only one piece of the picture.
What other tests go with RA factor?
Anti-CCP antibodies, ESR and CRP (for inflammation) and joint X-rays are commonly used together to assess rheumatoid arthritis.
Reviewed by Dr. Sanjay Anbu, MBBS. MedDroid is an AI medical assistant and can make mistakes. It provides general health information, not a diagnosis or medical advice — always consult a qualified clinician. In an emergency, contact your local emergency number immediately.