C-reactive protein (CRP) is plasma proteins which increase in concentration following infection, inflammation or trauma. CRP is so named because it is able to effect precipitation of somatic C-polysaccharide of Streptococcus pneumonia. It is synthesized in the liver and, in humans, is normally present as a trace constituent of serum at levels less than 0.5 mg/dl. The levels in serum rise quickly following acute tissue damage and also fall very rapidly once the stimulus is removed. It has been proposed that the function of CRP is to aid in complement activation, influence phagocytic cell function, and augment cell mediated cytotoxicity. For CRP at lower concentrations, e.g. 0.1 ~ 0.3 mg/dl, it is usually so-called high-sensitivity CRP (hsCRP). hsCRP is strongly suggested as a biomarker in clinics for the risk evaluation of heart attack.