降钙素原水平鉴别血流感染的研究

The Study of Identifying the Bloodstream Infection by Using Procalcitonin

目的探讨降钙素原(PCT)水平鉴别血流感染的价值。方法收集大理州人民医院2016年—2018年血培养分离出单一菌株、且在采集血培养的同时检测了血清PCT的患者资料;结合血流感染相关诊断标准,以及双套血培养单瓶报阳为污染菌的标准,将结果分为血流感染组和污染组;同时收集2018年血培养为阴性、且在采集血培养的同时检测了血清PCT的患者资料作为阴性对照组;统计分析比较三组的PCT水平。结果共收集血流感染组495例、污染组206例及阴性组2228例。PCT中位数感染组为5.83(0.89~42.93)ng/mL,分别与阴性组的0.22(0.05~1.05)ng/mL及污染组的0.27(0.08~1.39)ng/mL比较,差异有统计学意义,阴性组与污染组比较差异无统计学意义。PCT阈值为1.37ng/mL时鉴别血流感染与血培养阴性的尤登指数最大,受试者工作特征曲线(ROC曲线)下面积0.82,敏感度70.50%,特异度78.90%,95%可信区间(0.80,0.84),阳性预测值42.61%,阴性预测值92.33%。结论PCT水平在鉴别血流感染方面有一定的准确性,可作为初步鉴别血流感染或血培养污染的方法,但也要结合临床及血培养结果综合判定。

Objective To explore the value of using procalcitonin(PCT)for the identification of bloodstreaminfection.Methods Collecting the clinical information of patients which included a single bacterial strain had been isolated from their blood culture samples and the serum PCT results which were tested along with their blood culturing from 2016 to 2018.All the patients’data we collected were divided into the bloodstream infection group and the contamination group.The grouping operation based on the related criteria of bloodstream infection and the definition that as long as any single vial is position in blood culture can be recognized as the contaminated bacteria.The negative control group is the patients’data collected in 2018 which was the results of their blood culture were negative and the related PCT results had been tested as the other two groups.Finally,the PCT records were analyzed and compared among the three groups.Results Eventually,495 cases,206 cases and 2228 cases medical data were collected into the bloodstream infection group,the contamination group and the control group respectively.The mediansof PCT in three groups are significantly different in statistics,which are 5.83(0.89~42.93)ng/mL,0.22(0.05~1.05)ng/mL and 0.27(0.08~1.39)ng/mL respectively,while the difference of the figures between the negative group and the pollution group is not distinct.As for Youden’s index,the figure can be the largest when the PCT threshold value is set as 1.37ng/mL when identifying the results between bloodstream infection and negative blood culture,in this case,the proportion of area under the ROC curve is 0.82 as well as the sensitivity is 70.50%,the specificity is 78.90%,the 95% confidence interval is(0.80,0.84),the positive predictive value is 42.61%,and the negative predictive value is 92.33%.Conclusion It is accurate to some extent that identifying bloodstream infection by using PCT results,which can be regarded as a preliminary method to identify whether blood samples are infectedor contaminated,but it’s better to combine the clinical data and the blood culture results for comprehensive determination.