CRP and infectious disease: The laboratory detection of infectious diseases mainly focused on white blood cell (WBC), erythrocyte sedimentation rate (ESR) and N which were the basis for the application of antibacterial drugs; but the indexes which are lack of specificity may result in misdiagnosis and missed diagnosis, leading to delayed treatment and increased mortality.6 C-reactive protein (CRP) and procalcitionin (PCT) are both the resistance products which are generated when pathogenic microorganism invades human body and stimulates cells.