A C-reactive protein (CRP) test is a blood test that checks for inflammation in the body. CRP is a protein made by the liver that is released into the bloodstream in response to inflammation. The test measures the level of CRP in a sample of your blood, and high levels of CRP may indicate a serious health condition that causes inflammation. Inflammation is your bodys way of protecting your tissues and helping them heal from an injury, infection, or other disease. Inflammation can be acute (sudden) and temporary, which is usually helpful, or chronic (long-term), which can damage healthy tissues.

A CRP test can show whether you have inflammation in your body and how much, but it cannot show whats causing the inflammation or which part of your body is inflamed. The test is often done with the erythrocyte sedimentation rate (ESR) test, which also looks for inflammation. A more sensitive CRP test, called a high-sensitivity C-reactive protein (hs-CRP) assay, is available to determine a persons risk for heart disease.

A CRP test may be used to help find or monitor inflammation in acute and chronic infections, certain autoimmune disorders, and other diseases that can cause harmful chronic inflammation. It can also help diagnose a chronic inflammatory disease, such as rheumatoid arthritis or lupus, and determine if anti-inflammatory medicine is working to treat a disease or condition. Additionally, a high level of hs-CRP in the blood has been linked to an increased risk of heart attacks, and the hs-CRP test can help show the risk of getting coronary artery disease.

To prepare for a CRP test, no special preparation is needed in most cases, and the test is done by taking a blood sample from a vein. The normal CRP values vary from lab to lab, and the levels often increase slightly with age, female sex, and in African Americans. The majority of healthy adults have levels less than 0.3 mg/dL[[6]]...