C-reactive protein (CRP) concentration

Your doctor may order a C-reactive protein (CRP) test to check for inflammation in your body, help diagnose or rule out infections, monitor chronic conditions such as arthritis or autoimmune disease, and see how well a treatment is working over time.

Doctors may order CRP testing to check for signs of inflammation, monitor chronic conditions (such as rheumatoid arthritis or heart disease), or evaluate suspected infections. It can also help guide treatment decisions or monitor recovery from illness.

A high CRP level usually means there is inflammation somewhere in your body. This can occur with infections, injuries, chronic inflammatory diseases, or after surgery, but the test alone cannot show where the inflammation is located or what is causing it.

A higher-than-normal CRP level often indicates inflammation, which can be caused by infections, autoimmune diseases, or other health issues. However, a single test result alone isn’t diagnostic—your doctor will consider other factors, like symptoms and medical history.

A low or normal CRP level generally means there is no significant inflammation in your body at the time of testing, which can be reassuring, though your doctor will interpret the result alongside your symptoms, medical history, and other laboratory findings.

A low CRP level usually suggests minimal inflammation. However, it doesn’t rule out all causes of inflammation, so your doctor may still recommend further testing or follow-up.

This test is a simple blood draw. A healthcare provider will clean your skin, insert a small needle into a vein in your arm, collect a sample of blood into a tube, and send it to a laboratory. The procedure usually takes only a few minutes and causes minimal discomfort.

A small blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab, where it’s analyzed to measure CRP levels using a sensitive detection method.