C-reactive protein (CRP) by high-performance liquid chromatography (HPLC)

C-reactive protein (CRP) is a substance your liver makes when there is inflammation somewhere in your body, so measuring it helps you and your doctor understand and track your overall health.

CRP is a marker that rises when your body is fighting inflammation. It can signal infections, injuries, or conditions like arthritis or heart problems. While CRP itself isn’t a direct cause of illness, it helps guide treatment decisions by showing whether inflammation is active.

Your doctor may order this test if you have signs of infection or inflammation, such as fever, fatigue, or pain, or to help monitor ongoing conditions like arthritis, heart disease, or recovery after surgery.

Your doctor may order CRP testing if you have symptoms of inflammation, such as fever, joint pain, or swelling. It’s also used before surgeries, to check for hidden infections, or to monitor chronic conditions like rheumatoid arthritis or heart disease.

No special preparation is usually needed for a CRP blood test, but tell your care team about any medications, supplements, or recent illnesses, since these can sometimes influence what your results show.

You may receive this test via blood drawn from a vein in your arm. No special preparation is usually needed, but inform your doctor about any medications or recent illnesses that could affect results.

A high CRP level means inflammation is present somewhere in your body but does not point to an exact cause, so your doctor may suggest additional testing, repeat measurements, or a treatment plan based on your full picture.

Results are typically reported in milligrams per liter (mg/L). High CRP levels may prompt further testing for infections or autoimmune conditions, while low levels might mean inflammation is under control. Your doctor will discuss findings with you.