C-reactive protein (CRP) is a protein found in the blood which rises in level in response to inflammation.
CRP was first discovered as a substance in the serum of patients with acute inflammation that reacted with the C- (capsular) polysaccharide of pneumococcus and thus the name.
It was discovered by Tillett and Francis in 1930 and is synthesized in liver.
A rise in CRP occurs as acute phase response in a wide range of conditions like infections, inflammatory diseases, malignancy and autoimmune disordres. The levels of CRP rapidly increase within 2 hours of acute insult, reaching a peak at 48 hours.
An elevated CRP level does not diagnose a specific disease but is an indicator of inflammatory response that might occur in variety of conditions.
Scleroderma, polymyositis, and dermatomyositis and SLE do not cause a rise in CRP.
RP level is an independent risk factor for atherosclerotic disease. High CRP means higher risk of developing stroke, myocardial infarction, and severe peripheral vascular disease.
Normal concentration in healthy human serum is usually lower than 10 mg/L. CRP slightly increases with aging. Higher levels are also found in found in late pregnant women
CRP returns to normal more quickly than ESR in response to therapy.