C-reactive protein (CRP) concentration in serum/plasma

The C-reactive protein (CRP) test matters because it helps your doctor detect inflammation in your body, often before other symptoms become obvious. Since inflammation can signal infections, chronic conditions, or an increased risk of heart disease, this simple blood test provides valuable information that guides diagnosis and treatment decisions.

CRP is a marker for inflammation, which can occur due to infections, injuries, or conditions like arthritis or heart disease. High levels may signal an active inflammatory process that needs attention.

During the test, a healthcare professional will draw a small sample of blood from a vein in your arm, usually on the inside of the elbow. The procedure takes only a few minutes, and you may feel a quick sting or pinch when the needle goes in. Afterward, a small bandage will be placed on the spot, and you can return to your normal activities right away.

A blood sample is taken from a vein, usually in your arm. You may feel a slight pinch, but it’s quick and painless. No special preparation is needed unless instructed otherwise.

CRP testing is commonly used to check for infections, monitor autoimmune conditions such as rheumatoid arthritis or lupus, and evaluate inflammation after surgery. It can also help assess your risk for heart disease, sometimes using a high-sensitivity CRP (hs-CRP) test ordered alongside other lab work.

Doctors may order this test to check for infections, monitor chronic inflammatory conditions, or evaluate risk for heart disease. It’s also used to guide treatment decisions for conditions like rheumatoid arthritis.

Results are typically reported in milligrams per liter (mg/L), and your doctor will interpret them based on your overall health and symptoms. A normal level suggests little inflammation, while an elevated level may point to an infection or another inflammatory condition. If your results are high, your doctor may order additional tests, repeat the CRP test, or adjust your treatment plan as needed.

Results may be reported as a numerical value, but reference ranges vary by lab. High levels often prompt further investigation, such as additional blood tests or imaging, to identify the cause of inflammation.