Rheumatoid Factor Test

Rheumatoid factor test is used by health-care professionals to help in diagnosing rheumatoid arthritis. Sometimes rheumatoid factor can be detected in the blood of normal individuals and of those with other autoimmune diseases that are not rheumatoid arthritis. In people with rheumatoid arthritis, high levels of rheumatoid factor can indicate a tendency toward more aggressive disease and/or a tendency to develop rheumatoid nodules and/or rheumatoid lung disease. Rheumatoid factor is an antibody that is measurable in the blood with a routine blood test. Rheumatoid factor is actually an antibody that can bind to other antibodies. Antibodies are normal proteins in our blood that are important parts of our immune system. Rheumatoid factor is an antibody that is not usually present in the normal individual. Because rheumatoid factor antibody binds to normal antibodies, it can be generally referred to as an autoantibody. Health-care professionals use the rheumatoid factor test to assist in the diagnosis of rheumatoid arthritis. Rheumatoid factor is sometimes abbreviated as "RF."

During a rheumatoid factor test, a small sample of blood is drawn from a vein in your arm. This typically takes just a few minutes. Your blood sample is sent to a laboratory for testing.

High levels of rheumatoid factor (rheumatoid factor "positive") are associated with a tendency toward more severe rheumatoid disease. This factor is also associated with a higher tendency to develop non-joint manifestations of rheumatoid disease, such as rheumatoid nodules and rheumatoid lung disease.

The RF test is a simple blood test. During the test, a healthcare provider draws
blood from a vein in your arm or the back of your hand. The blood draw only
takes a few minutes. For it, the provider will:

1. clean the skin over your vein
2. tie an elastic band around your arm so the vein fills quickly with blood
3. insert a small needle into the vein
4. collect your blood in a sterile vial attached to the needle
5. cover the puncture site with gauze and an adhesive bandage to stop any
bleeding
6. send your blood sample to a lab to be tested for the RF antibody