尿类酵母菌测定和镜检对尿路真菌感染的诊断准确性研究

Predictive Value of Urine Yeast-like Fungi and Microscopic Fungi Count on Urinary Tract Fungal Infection

目的探讨Sysmex UF-1000i尿液流式分析仪尿类酵母菌测定和镜检真菌计数对于尿路真菌感染的早期预测价值。方法应用前瞻性临床诊断试验研究方法,对2012年1月—2013年5入住月桂林医学院附属医院重症医学科并留置尿管患者233例,取中段尿标本,同时送检行尿液流式分析仪检测、尿标本镜检及尿培养检查,以尿培养为金标准,比较尿类酵母菌测定及镜检的诊断价值,并绘制受试者工作特征(ROC)曲线,评价尿类酵母菌测定诊断真菌感染的敏感度及特异度,确定其诊断临界值。结果尿液流式分析仪尿类酵母菌测定诊断尿路真菌感染的敏感度为87.88%,特异度为65.67%,阳性预测值为65.41%,阴性预测值为88.00%;镜检诊断尿路真菌感染的敏感度为49.49%,特异度为95.52%,阳性预测值为89.09%,阴性预测值为71.91%。尿类酵母菌测定与镜检比较敏感度提高,特异度降低(P<0.05)。尿类酵母菌测定对尿路真菌感染诊断的ROC曲线下面积为(0.864±0.026),95%CI为(0.814,0.915),P=0.00。尿类酵母菌以76.2个/μl为诊断临界值时,敏感度为77.77%,特异度为88.06%,阳性预测值为82.79%,阴性预测值为84.28%,Youden指数为0.659。结论诊断尿路真菌感染时尿类酵母菌测定敏感度较高,镜检特异度较高,尿类酵母菌测定联合镜检分析有助于早期预测患者尿路真菌感染的风险。

Objective To study the early predictive value of detecting urine yeast -like fungi by urine flow cytometer Sysmex UF - 1000i and microscopic fungi count on urinary tract fungal infection. Methods A prospective clinical diagnostic test study involving 233 urine specimens of inpatients with indwelling catheter in intensive care units （ICU） on January 2012 to May 2013 was conducted. Urine yeast - like fungi were detected by using Sysmex UF - 1000i urine flow cytometer and urine fungi count was detected by microscope and urine culture. The positive urine fungi culture was taken as ＂ gold standard＂ , and the diagnostic value of urine yeast - like fungi and urine fungi counts was compared. Receiver - operating characteristic （ ROC ） curve was used to assess the diagnostic sensitivity and specificity of yeast - like fungi in urinary fungal infection and its diagnostic threshold was also determined. Results The sensitivity, specificity, positive predictive value and negative predictive value of yeast - like fungi detection for urine tract fungal infection were 87.88% , 65.67% , 65.41% and 88.00% respectively; And urine fungi detection by microscope were 49. 49% , 95.52% , 89. 09% and 71.91% respectively. Sensitivity of the determination of yeast - like fungi was better than microscopic examination, but lower than the microscopy in specificity （ P 〈 0. 05 ） . The area under the ROC curve of yeast -like fungi in diagnosis of urinary tract fungal infection was （0. 864 ± 0. 026 ） , 95 % CI was （0. 814, 0. 915 ） , P = 0. 00. When 76. 2/μl was used as cut - off value, the diagnostic sensitivity, specificity, positive predictive value and nega- tive predictive value were 77.77%, 88.06%, 82. 79% and 84. 28% , and the Youden index was 0. 659. Conclusion The sensitivity of yeast - like fungi detection is better in detecting urine tract fungal infection, but specificity of microscopic examination is higher. Combination of urine yeast - like fungi and microscopic yeast count can help predict the risk of urinary tract fungal infection in an early stage.