What is the C-reactive protein (CRP) test?

This blood test measures a substance made by the liver called C-reactive protein, or CRP. The level of CRP in your blood goes up when there is inflammation (swelling and irritation) in the body. There are 2 different CRP tests.

• Standard CRP
• High-sensitivity CRP (hs-CRP, also called ultra-sensitive CRP or us-CRP)

Why is this test done?

The CRP test may help diagnose and treat a medical problem you are having. It does not diagnose a specific problem but it can help your healthcare provider know what other tests you might need. It’s also a way to see how well treatment for a disease is working.

The high-sensitivity CRP test (hs-CRP) can measure much smaller amounts of CRP than the standard CRP test. It’s used to check for inflammation of the blood vessels. The hs-CRP test is recommended only if you have a moderate risk of heart disease. It is done to see if you should have more treatment to help prevent a heart attack or other problems caused by heart disease. Your healthcare provider will evaluate your risk for heart disease and determine if you should have the hs-CRP test.

How do I prepare for this test?

• You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your healthcare provider knows about any medicines, herbs, or supplements that you are taking. Ask your provider before stopping any of your regular medicines.
• Talk to your healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. A small amount of blood is taken from a vein in your arm with a needle. The blood is collected in tubes and sent to a lab.

Ask your healthcare provider when and how you will get the result of your test.

What do the test results mean?

Your CRP level may be higher than normal if you have a disease that is causing inflammation, such as:

• An infection
• Inflammatory bowel disease
• Some types of arthritis
• Coronary artery (heart) disease
• An autoimmune disease (a disease that causes your body to mistakenly attack your own tissues), such as lupus.

What if my test result is not normal?

Test results are only one part of a larger picture that takes into account your medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your healthcare provider about your result and ask questions, such as.

• If you need more tests
• What kind of treatment you might need
• What lifestyle, diet, or other changes you might need to make