C-Reactive Protein (CRP) is an acute-phase reactant protein produced by the liver in response to inflammation, infection, or tissue injury. This test measures the level of CRP in the blood, which rises rapidly (within 6-12 hours) and can increase up to 1000-fold during inflammatory processes. CRP is a more sensitive and rapidly responding indicator of inflammation compared to the erythrocyte sedimentation rate (ESR). Elevated CRP levels can indicate various inflammatory conditions including bacterial infections, autoimmune diseases, tissue injury, and certain cancers. The test is particularly useful for monitoring the response to anti-inflammatory therapy and detecting postoperative complications. High-sensitivity CRP (hs-CRP) has also been used as a marker for cardiovascular disease risk assessment. CRP levels typically return to normal within a few days after the inflammatory stimulus resolves, making it valuable for monitoring disease activity and treatment effectiveness.