Rheumatoid Factor: About Your Child's Test

What is it?

A rheumatoid factor (RF) blood test measures the amount of the RF antibody in your child's blood. The RF antibody can damage normal body tissue.

A high RF level can be caused by diseases like rheumatoid arthritis. It's also caused by some infections. Sometimes healthy people can have a high RF level.

Why is this test done?

The test is done to help confirm that your child has arthritis or some other inflammatory condition.

How do you prepare for the test?

You don't need to do anything before your child has this test.

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?

  • Your child will likely be able to go home right away.
  • Your child can go back to his or her usual activities right away.

Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor if your child is having problems. Ask your doctor when you can expect to have your child's test results.

Where can you learn more?

Go to https://www.healthwise.net/patientEd

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