C-reactive protein (CRP) is an acute-phase serum protein synthesized by the liver in response to interleukin-6 (IL-6) during inflammation. The name of CRP derives from its ability to react with the C polysaccharide of Streptococcus pneumoniae. CRP is an annular,pentameric protein that belongs to the pentraxin family of proteins. CRP displays several functions associated with host defense: it promotes agglutination,bacterial capsular swelling,phagocytosis and complement fixation through its calcium-dependent binding to phosphorylcholine. It is used mainly as a marker of inflammation.