Jacob Mary S, Kulie Paige, Benedict Cameron, Ordoobadi Alexander J, Sikka Neal, Steinmetz Erika, McCarthy Melissa L
Washington Adventist Hospital, Emergency Department, United States.
George Washington Medical Faculty Associates, Department of Emergency Medicine, United States.
Am J Emerg Med. 2018 Jan;36(1):61-65. doi: 10.1016/j.ajem.2017.07.016. Epub 2017 Jul 8.
Urine microscopy is a common test performed in emergency departments (EDs). Urine specimens can easily become contaminated by different factors, including the collection method. The midstream clean-catch (MSCC) collection technique is commonly used to reduce urine contamination. The urine culture contamination rate from specimens collected in our ED is 30%. We developed an instructional application (app) to show ED patients how to provide a MSCC urine sample. We hypothesized that ED patients who viewed our instructional app would have significantly lower urine contamination rates compared to patients who did not.
We prospectively enrolled 257 subjects with a urinalysis and/or urine culture test ordered in the ED and asked them to watch our MSCC instructional app. After prospective enrollment was complete, we retrospectively matched each enrolled subject to an ED patient who did not watch the instructional app. Controls were matched to cases based on gender, type of urine specimen provided, ED visit date and shift. Urinalysis and urine culture contamination results were compared between the matched pairs using McNemar's test.
The overall urine culture contamination rate of the 514 subjects was 38%. The majority of the matched pairs had a urinalysis (63%) or urinalysis plus urine culture (35%) test done. There were no significant differences in our urine contamination rates between the matched pairs overall or when stratified by gender, by prior knowledge of the clean catch process or by type of urine specimen.
We did not see a lower contamination rate for patients who viewed our instructional app compared to patients who did not. It is possible that MSCC is not effective for decreasing urine specimen contamination.
尿液镜检是急诊科常见的检查项目。尿液标本很容易受到包括采集方法在内的不同因素污染。中段清洁尿（MSCC）采集技术常用于减少尿液污染。我们急诊科采集的标本的尿培养污染率为30%。我们开发了一款指导性应用程序（应用），向急诊科患者展示如何提供MSCC尿液样本。我们假设，与未观看我们指导性应用的患者相比，观看该应用的急诊科患者的尿液污染率会显著降低。
我们前瞻性纳入了257名在急诊科接受尿液分析和/或尿培养检查的受试者，并要求他们观看我们的MSCC指导性应用。前瞻性纳入完成后，我们回顾性地将每名纳入的受试者与一名未观看指导性应用的急诊科患者进行匹配。根据性别、提供的尿液标本类型、急诊科就诊日期和班次将对照组与病例组进行匹配。使用McNemar检验比较匹配对之间的尿液分析和尿培养污染结果。
514名受试者的总体尿培养污染率为38%。大多数匹配对进行了尿液分析（63%）或尿液分析加尿培养（35%）检查。在总体匹配对之间，或按性别、对清洁中段尿采集过程的既往了解情况或尿液标本类型分层时，我们的尿液污染率均无显著差异。
与未观看我们指导性应用的患者相比，观看该应用的患者的污染率并未降低。中段清洁尿采集可能对减少尿液标本污染无效。
