C-reactive protein (CRP) in serum/plasma

Your doctor may order a CRP test to check for inflammation in your body. The liver makes C-reactive protein (CRP) when there is swelling, infection, or tissue damage anywhere in the body. This test helps detect and monitor conditions such as infections, autoimmune disorders, and chronic inflammatory diseases, and it can show how well your treatment is working.

Your doctor may order a CRP test to check for signs of inflammation. This can help diagnose conditions like infections (e.g., pneumonia, urinary tract infections), autoimmune diseases (e.g., rheumatoid arthritis), or to monitor chronic conditions like heart disease or kidney problems. It may also be used before surgery to assess risk or after treatment to see if inflammation is improving.

A high CRP level usually means that there is inflammation somewhere in your body. Common causes include infections, recent surgery or injury, and autoimmune conditions such as rheumatoid arthritis or lupus. The test cannot show where the inflammation is located or what is causing it, so your doctor will probably order additional tests to find the source.

A higher than expected CRP level often indicates inflammation. While elevated CRP can signal infections or other inflammatory conditions, it doesn’t always pinpoint the exact cause. For example, it may rise with fever, stress, or certain medications.

A low or normal CRP level generally means that you do not have significant inflammation in your body at the time of testing. This can be reassuring, but it does not completely rule out every health problem, since some conditions do not raise CRP. If your symptoms continue, your doctor may repeat the test or explore other possible causes.

A low CRP level usually means there’s little to no inflammation in your body. However, very low levels might also occur in certain genetic conditions or with certain medications.

The CRP test is a simple blood test that is done in a lab, clinic, or hospital. A health care professional will clean the skin, place a band around your upper arm, and draw a small blood sample from a vein, usually in your arm. The sample is sent to a laboratory, and results are often ready within a day or two. The procedure takes only a few minutes and carries very little risk.

A blood sample is taken 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 immunoassay method.