C-Reactive Protein (CRP)
A C-reactive protein (CRP) test is a blood test that measures the amount of a protein called C-reactive protein in your blood. C-reactive protein measures general levels of inflammation in your body.
High levels of CRP are caused by infections and many long-term diseases. But a CRP test cannot show where the inflammation is located or what is causing it. Other tests are needed to find the cause and location of the inflammation.
Why It Is Done
A C-reactive protein (CRP) test is done to:
- Check for infection after surgery. CRP levels normally rise within 2 to 6 hours of surgery and then go down by the third day after surgery. If CRP levels stay elevated 3 days after surgery, an infection may be present.
- Identify and keep track of infections and diseases that cause inflammation, such as:
- Check to see how well treatment is working, such as treatment for cancer or for an infection. CRP levels go up quickly and then become normal quickly if you are responding to treatment measures.
A special type of CRP test, the high-sensitivity CRP test (hs-CRP), may be done to help find out your risk of a heart attack and stroke. The results can help you and your doctor make decisions about how to lower your risk. The connection between hs-CRP levels and the risk of heart attack and stroke are not understood completely. But high levels may mean that the lining of your arteries are inflamed. This may damage the arteries and raise your risk of a heart attack and stroke.