Rheumatoid factor (RF) is an antibody. Unlike most antibodies produced by your body’s immune system, it doesn’t target bad bacteria and other invaders. Instead, this protein turns against your body’s own cells and tissues. It binds with your normal antibodies that are trying to fight off infection. It can be a sign that you are developing an autoimmune disease.

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What is a rheumatoid factor test?

A rheumatoid factor test is a blood test. It measures the amount of the protein known as rheumatoid factor in your blood. High levels can be a sign of rheumatoid arthritis, an autoimmune disease.

Why is a rheumatoid factor test important?

Rheumatoid factor isn’t always present in your body. When it shows up, it can be a sign of an autoimmune disease, such as rheumatoid arthritis.

When do you need a rheumatoid factor test?

Your healthcare provider might recommend a test if you have ongoing problems with your joints, such as pain, swelling or stiffness. Coupled with some other tests, the rheumatoid factor test can help your provider find the problem. If you are diagnosed with rheumatoid arthritis, talk to your provider about the right treatment for you.

What should you expect with a rheumatoid factor test?

You don’t have to do anything special to prepare for this test. A technician will draw blood from a vein in your arm. The blood sample will go to a lab for analysis. An elevated level of rheumatoid factor is 14 IU/mL or higher.

CareNow® Can Help

If you’re experiencing pain and stiffness in your joints, especially in your hands, feet or knees, visit your nearest CareNow® urgent care clinic for your healthcare needs.

You can minimize your wait time by using our Web Check-In®.

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