Etiological Screening Of Lower Respiratory Tract Infection In Children And The Clinical Application Of Procalcitonin

Objective:Through the screening of pathogenic microorganisms in 67 cases of preschool children(3-7 years old)with lower respiratory tract infection in Baotou,Inner Mongolia,the children with lower respiratory tract infection were divided into observation group according to the pathogenic microbial speciesand control group in accordance with 3-7 year-old children with normal physical examination.The levels of procalcitonin and C-reactive protein in serum were measured respectively to distinguish the type of infection in children with lower respiratory tract infection through the study ofPCT and CRP,the application of PCT and CRP in children with lower respiratory tract infection was studied.The aim of the research is to accelerate the diagnosis and help design the accurate treatment.Methods:The deep sputum samples of children were selected for bacterial culture and identification.3-5mL of venous blood was taken within 12 hours after admission to screen the pathogens of respiratory pathogens by indirect immunofluorescence method.The chemiluminescence method was used to perform procalcitonin measurement and the C-reactive protein was determined by latex-enhanced immunoturbidimetric method.The data were divided into three groups,i.e.bacterial infection group,non-bacterial infectiongroupand mixed infection group.SPSS 18.0 was used to analyze the experimental data.Because the normal distribution was not satisfied,rank-sum test was applied and P<0.05 was used as the standard for statistically significant difference.Results:The ROC curves showed that when the detection was single,the area under the CRP curve was smaller than the area under the PCT curve.Jorden index of CRP was 0.359,the sensitivity was 59.7%,and the specificity was 76.2%.The Jorden index of PCT was 0.72,the sensitivity was 91%,and the specificity was 81%.The application of Logistic regression fitting ROC curve showed that when the detection of CRP and PCT were combined,the Jorden index was 0.788,the sensitivity was 83.6%,and the specificity was 95.2%,the area under the ROC curve was 0.948,and the area was larger than the measured area alone.Conclusion:In this study,we found that the PCT did show differences in the lower respiratory tract infection caused by the different pathogens in the bacterial infection group,non-bacterial infection group and mixed infection group,as were indicated by the level of PCT and CRP in above three groups.PCT can be used as a reference for the identification of pathogens in lower respiratory tract infection,and in combination with CRP,it can also evaluate the degree of infection in children,leading to a certain guiding significance of the clinical diagnosis and treatment and rational administration.