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Rheumatoid Factor

What is it?

Rheumatoid (REW-muh-toid) factor (RF) is a blood test to screen for Rheumatoid arthritis (RA). Rheumatoid arthritis is an autoimmune (au-toe-ih-MEWN) disease that causes swelling of the joints and the wearing away of bone and joint tissue. The joints of your hands, fingers, wrists, and toes are most often affected, but all joints can be involved. An autoimmune disease is when your immune system attacks the tissues of your own body. The immune system is normally supposed to protect you against disease.

Why do I need it?

If you feel stiff in the mornings for at least 6 weeks your caregiver may want you to be tested for RA. Other reasons to be tested may be pain or swelling in at least 1 joint for the past 6 weeks. Subcutaneous (sub-que-TAIN-e-us) nodules, or knob-like swelling under the skin, are also reasons to test for RA.

How do I get ready for the test?

Your caregiver will tell you when to have your blood test done. The blood test may be done before or after eating.

How is the specimen collected?

A caregiver will put a wide rubber strap around your arm and tighten it. Your skin will be cleaned with alcohol. A small needle attached to a special test tube will be put into a vein in your arm or hand. The tube has suction to pull the blood into it. When the tube is full, the rubber strap, needle and tube are removed. The caregiver will press a piece of cotton where the needle was removed. You may be asked to hold the cotton on the area for a few minutes to help stop the bleeding. Tape may then be put over the cotton on your arm.

What do I do after the test?

You may remove the tape and cotton in about 20 to 30 minutes. Call your caregiver to get the results of your test. Your caregiver will explain what your test results mean for you. Follow the instructions of your caregiver.

Care Agreement

You have the right to help plan your care. To help with this plan, you must learn about your lab tests. You can then discuss the results with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.