ObjectiveTo study the value of procalcitonin (PCT) in the prediction and differentiation of peripancreatic infection in severe acute pancreatitis (SAP) patients. MethodsOne hundred and two SAP patients were divided into  infected pancreatic necrosis group  (IPN group, n=18) and noninfection group (NI group, n=84) according to whether peripancreatic infection developed during the first 2 weeks of hospitalization. Serum PCT values of patients were monitored daily by quantitative (RIA) and semiquantitative (PCT QUEST)  methods. The peak values of PCT before the infection were recorded and analyzed. ResultsSerum PCT level of IPN group was (17.78±3.61)ng/mL, which  was significantly higher than  (11.74±3.25)ng/mL  of NI group (t=7.19,  P<0.01).  If the threshold value of serum PCT was set as 15ng/ml, the sensitivity and specificity of detecting infection was 83.33% and  77.38% respectively. Semiquantitative test of PCT showed a significant difference between the two groups, setting “++” as the threshold, the sensitivity and specificity of detecting infection were 94.44% and 39.29% respectively (χ2=6.17, P<0.05); and setting “+++” as the threshold, they were 61.11% and 96.43% respectively (χ2=36.73, P<0.01). ConclusionPCT detection is of great value in the prediction and differentiation of early peripancreatic infection in SAP patients.