Scherz Valentin, Durussel Christian, Greub Gilbert
Institute of Microbiology, University of Lausanne and University Hospital Center, Lausanne, Switzerland.
PLoS One. 2017 Nov 14;12(11):e0187263. doi: 10.1371/journal.pone.0187263. eCollection 2017.
Given the importance of microbiology results on patient care, high quality standards are expected. Internal quality assurance (IQA) could mitigate the limitations of internal quality control, competency assessment and external quality assurance, adding a longitudinal insight, including pre- and post-analytical steps. Here, we implemented an IQA program in our clinical microbiology facilities with blind resubmission of routine samples during 22 months. One-hundred-and-twenty-one out of 123 (98.4%) serological analyses and 112 out of 122 (91.8%) molecular analyses were concordant. Among the discordances in molecular biology analyses, 6 results were low positive samples that turned out negative, likely due to stochastic repartition of nucleic acids. Moreover, one identified retranscription error led us to implement automated results transmission from the Applied Biosystems instruments to the laboratory information system (LIS). Regarding Gram stain microscopy, 560 out of 745 (75.2%) of compared parameters were concordant. As many as 67 out of 84 (79.8%) pairs of culture results were similar, including 16 sterile pairs, 27 having identical identification or description and semi-quantification and 24 only showing variations in semi-quantification with identical description or identification of colonies. Seventeen pairs had diverging identification or description of colonies. Culture was twice only done for one member of the pairs. Regarding antibiotic susceptibility testing, a major discrepancy was observed in 5 out of 48 results (10.4%). In conclusion, serological tests were highly reproducible. Molecular diagnosis also revealed to be robust except when the amounts of nucleic acids present in the sample were close to the limits of detection. Conventional microbiology was less robust with major discrepancies reaching 39.5% of the samples for microscopy. Similarly, culture and antibiotic susceptibility testing were prone to discrepancies. This work was ground for reconsidering multiples aspects of our practices and demonstrates the importance of IQA to complete the other quality management procedures.
鉴于微生物学检测结果对患者护理的重要性，人们期望有高质量标准。内部质量保证（IQA）可以减轻内部质量控制、能力评估和外部质量保证的局限性，提供纵向洞察，包括分析前和分析后步骤。在此，我们在临床微生物学设施中实施了一项IQA计划，在22个月内对常规样本进行盲态重新提交。123项血清学分析中有121项（98.4%）、122项分子分析中有112项（91.8%）结果一致。在分子生物学分析的不一致结果中，6个结果为低阳性样本，最终结果为阴性，可能是由于核酸的随机分布。此外，一个确定的重新转录错误促使我们实施了从Applied Biosystems仪器到实验室信息系统（LIS）的自动结果传输。关于革兰氏染色显微镜检查，745个比较参数中有560个（75.2%）结果一致。84对培养结果中有67对（79.8%）相似，包括16对无菌培养结果、27对具有相同的鉴定或描述及半定量结果，以及24对仅在半定量上有差异但菌落描述或鉴定相同。17对培养结果的菌落鉴定或描述存在差异。培养仅对其中一对中的一个成员进行了两次。关于抗生素敏感性测试，48个结果中有5个（10.4%）存在主要差异。总之，血清学检测具有高度可重复性。分子诊断也显示出可靠性，除非样本中核酸的量接近检测限。传统微生物学的可靠性较低，显微镜检查中主要差异样本占比达39.5%。同样，培养和抗生素敏感性测试也容易出现差异。这项工作为重新考虑我们实践的多个方面奠定了基础，并证明了IQA对完善其他质量管理程序的重要性。
