C-Reactive Protein (CRP) Test: About This Test

What is it?

This blood test measures the amount of C-reactive protein in your blood. C-reactive protein levels rise when there is inflammation in your body.

Very high levels of CRP are caused by infections and many serious diseases. But other tests are needed to find the actual cause and location of the inflammation.

Why is this test done?

This test is used to:

• Check for infection after surgery.
• Find out if you have an increased chance of having a sudden heart problem, such as a heart attack.
• Identify and keep track of infections and diseases that cause inflammation, such as:
  • Lymphoma (cancer of the lymph nodes).
  • Giant cell arteritis (painful swelling of the blood vessels in the head and neck).
  • Rheumatoid arthritis (painful swelling of the tissues that line the joint).
  • Osteomyelitis (infection of a bone).

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. It depends on the reason for the test.
• You can go back to your usual activities right away.