It was confirmed in the present study that the level of PCT was positively correlated to the severity of the disease in children with sepsis(p=0.00); multivariate logistic regression analysis suggested that PCT was a related indicator for sepsis (p=0.000); the AUC of PCT was 86.3%, with a sensitivity of 83.230% and a specificity of 86.417%, which were higher than those of DD and FIB. The gene discussed is CALCA; the disease is Sepsis.