What is this test?
Rheumatoid factor is a group of antibodies that can be found in rheumatoid arthritis, but also in other conditions or in people without symptoms.
Why might it be ordered?
- For persistent pain, morning stiffness or joint swelling.
- To complement rheumatoid arthritis assessment along with Anti-CCP, inflammatory markers and examination.
What sample is needed?
A healthcare professional collects a venous blood sample. Depending on the method, the laboratory uses serum or plasma.
How should you prepare?
Tell the laboratory about all medicines, hormone treatments, vitamins and supplements you take. Do not stop or change treatment unless your clinician tells you to. Follow any instructions about fasting and the time of collection.
How should you understand the result?
A positive RF can support the diagnosis only with appropriate symptoms. A negative RF does not rule out seronegative rheumatoid arthritis. A positive result means the tested antibodies were detected, but it does not establish a diagnosis on its own. A negative result does not rule out every autoimmune condition.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.