尿沉渣细菌定量检查与尿培养检测结果的相关性分析

Correlation of quantitative examination of urinary sediment bacteria and urine culture

目的评价尿沉渣细菌定量检查作为筛选尿路感染指标的可行性。方法收集门诊及住院患者标本191例,先做尿培养,用余下的尿液做尿沉渣细菌定量检查,以细菌培养结果为标准,绘制受试者工作特征曲线(ROC)曲线,求出白细胞和细菌计数对尿路感染的诊断阈值,并计算其灵敏度、特异度、准确率、假阴性/假阳性率和阴/阳性预测值。结果尿细菌培养阳性的标本占39.7%,其中最常见的致病菌是大肠埃希菌;尿路感染的诊断阈值,细菌计数为1 024.5个/微升,白细胞计数为135.8个/微升。白细胞和细菌计数联合测定对尿路感染检查的最佳灵敏度为62.5%、特异度为98.1%、阳性预测值为95.7%、阴性预测值为79.6%、假阳性率为1.9%、假阴性率为37.5%、准确率为83.8%。结论尿沉渣细菌定量计数联合白细胞计数可作为泌尿系统感染的一项快速筛查指标,可筛除大部分阴性结果,尤其对细菌培养阳性结果的预测性较高,但仍然不可替代定量细菌培养。

Objective To evaluate quantitative examination of urinary sediment bacteria as a basic feasibility of screening indicators for urinary tract infection .Methods 191 outpatients and inpatient specimens were gathered firstly to implement a urine culture ,and then the rest of the urine were used for sediment bacteria quantitative testing .Meanwhile ,bacterial culture was conducted as the standard .According to the results of bacterial culture ,receiver operating characteristic（ROC） was drawn ,the threshold values of leukocyte and bacteria counts for diagnosis of urinary tract infection were found out and its sensitivity ,specificity ,positive / negative predictive value ,false positive/false negative rate and accuracy were calculated .Results The positive rate of urine culture was 39 .7% ,and the most common pathogen was Escherichia coli .The threshold value of bacteria and leukocyte counts for diagnosis of urinary tract infection was 1 024 .5/μL and 135 .8/μL respectively .When combined leukocyte and bacteria counts for urinary tract infection ,the optimum sensitivity was 62 .5% ,specificity was 98 .1% ,positive predictive value was 95 .7% ,negative predictive value was 79 .6% ,false positive rate was 1 .9% ,false negative rate was 37 .5% ,and accuracy was 83 .8% .Conclusion With UF‐1000i urinary sediment analyzer ,the combined determination of leukocyte and bacteria counts can remove the great mass of negative results ,Especially the results of bacterial culture positive predictability is higher ,but still can not replace of quantitative bacterial culture .