C-reactive protein is one of the body's most sensitive markers of acute inflammation. Levels rise rapidly within hours of an inflammatory trigger and fall quickly once the stimulus resolves, making CRP useful for both detecting and tracking inflammatory processes.
The quantitative CRP test is used to evaluate suspected bacterial infection, monitor activity of autoimmune diseases like rheumatoid arthritis and inflammatory bowel disease, assess response to anti-inflammatory therapy, and investigate unexplained fever or pain. This is distinct from the high-sensitivity (hs-CRP) version used for cardiovascular risk assessment. Sample type is serum, and no special preparation is required.