C-reactive protein (CRP) is a pentameric acute phase reactant discovered in 1930 in pneumococcal pneumonia patients. CRP present only in small amounts in normal healthy individuals and is involved in process of innate immune system with functions of compliment activation, antigen clearance and mediation of phagocytosis by activation neutrophills. CRP is synthesized by the liver and Its production is controlled primarily by interleukin-6. The serum CRP concentration may increase upto 1000-folds with infection, trauma, surgery, and other acute inflammatory events. In healthy individuals CRP levels are found in trace amounts, i.e. < 0.3 mg/l. Serum levels of CRP could exceed 100 mg/l or more in the presence of overwhelming systemic infection making it a positive acute phase reactant with a very short half life of 5-7 hours. Thus advantage of having short half life makes CRP levels as sensitive diagnostic indicators of infection.