C-reactive protein (CRP) in serum/plasma

This test measures the amount of C-reactive protein (CRP) in your blood. Your liver produces CRP when there is inflammation somewhere in your body. Your doctor may order this test to help detect infections, autoimmune disorders, or other inflammatory conditions, or to monitor how well a treatment is working over time.

Your healthcare provider may order this test to check for signs of inflammation, monitor chronic conditions like arthritis or heart disease, or evaluate symptoms such as fever, joint pain, or swelling that may suggest an infection or other inflammatory process.

In most cases, you do not need to do anything special to prepare for a CRP blood test, and you can usually eat and drink normally beforehand. Tell your doctor about any prescription medicines, vitamins, or supplements you take, since some drugs can affect the results. Wear a shirt with a sleeve that can be rolled up easily for the blood draw.

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves drawing blood from a vein, but this depends on your provider’s instructions. Avoid strenuous activity or certain medications that might affect results.

A health care professional will draw a small sample of blood, usually from a vein in your arm. They will clean the skin, wrap a band around your upper arm, and insert a thin needle to collect the sample. You may feel a quick pinch or sting, but the procedure typically takes less than five minutes, and the sample is then sent to a laboratory.

A healthcare professional will insert a small needle into a vein in your arm to draw blood. You may feel a slight pinch, but it’s usually over quickly. The blood is then sent to a lab for analysis.

Higher-than-normal CRP levels indicate that inflammation is present in your body, but this test alone cannot show where the inflammation is or what is causing it. Your doctor will interpret your results together with your symptoms, physical exam, and other laboratory tests. A normal result generally means no significant inflammation was detected. Always discuss your results with your doctor to fully understand what they mean for your health.

Results are interpreted based on your medical history and symptoms. Higher-than-normal levels may indicate inflammation, infection, or other health issues, while lower levels may suggest no active inflammation. Your provider will discuss the results with you.