Objective To explore the value of serum procalcitonin detection in judging whether severe patients complicate with infection.Methods 188 patients in the intensive care unit (ICU)were collected and divided into the infection and non-infection groups.The serum procalcitonin(PCT),C-reactive protein(CRP),total number of white blood cells(WBC)and neutrophile cell ratio were simultaneously monitored;41 cases in the infection group dynamically monitored PCT and related indicators for continuous 1-6 d and the statistical analysis was conducted.Results The age,PCT and CRP had statistically significant differences between the infection group(112 cases)and non-infection group(76 cases).Except the correlation of PCT and CRP in the infection group showing statistical significance,the comparison of the other indicators had no statistical differences.In the infectors,the PCT value comparison between on 1 d and 2 d in the hospital discharge group(32 cases)and the death group (9 cases)showed P >0.05,the PCT value comparison between on 3-6 d showed P <0.05.Conclusion Serum PCT is an effective indicator to judge whether se-vere infected patient has infection and is significantly superior to the traditional inflammatory indicators.Dynamically monitoring the PCT level in the critical patients has a certain value to judge the control situation of infection.