Rheumatoid Factor: About This Test

What is it?

A rheumatoid factor (RF) blood test measures the amount of the RF antibody in your blood. The RF antibody can attach to normal body tissue. This can cause damage.

A high RF level can be caused by several autoimmune diseases. These include rheumatoid arthritis and some infections. Sometimes healthy people have a high level of RF.

Why is this test done?

A test for rheumatoid factor is done to help support a diagnosis of rheumatoid arthritis.

How do you prepare for the test?

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How is the test done?

A health professional uses a needle to take a blood sample, usually from the arm.

How long does the test take?

The test will take a few minutes.

What happens after the test?

• You will probably be able to go home right away.

• You can go back to your usual activities right away.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to keep a list of the medicines you take. Ask your doctor when you can expect to have your test results.

Current as of: May 13, 2023

Content Version: 14.0

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