Operational feasibility and multi-centric evaluation of ‘TB<i>Detect</i> sputum microscopy kit’ for the direct detection of <i>Mycobacterium tuberculosis</i> in field settings

India relies primarily on direct smear microscopy for tuberculosis (TB) diagnosis. However, the low sensitivity of smear microscopy emphasizes the need to improve its performance. We recently described the development of ‘TB<i>Detect</i>’ kit which showed improved performance over direct smear microscopy at National Reference Laboratories (NRLs) in India. The present study was aimed to assess the operational feasibility of ‘TB<i>Detect</i>’ microscopy in field settings. This was evaluated by (i) assessing the performance of ‘TB<i>Detect</i>’ microscopy <i>vs.</i> LED-fluorescence microscopy (LED-FM) on consecutive presumptive pulmonary TB patients (<i>n</i> = 5300) who attended Designated Microscopy Centres (DMCs, <i>n</i> = 13) under 4 NRLs at Bhubaneswar, Bhopal, Chennai, and New Delhi, and (ii) obtaining feedback from Scientists (<i>n</i> = 10) and laboratory technicians (<i>n</i> = 42) using semi-structured questionnaires under the following parameters: feasibility of initiation of ‘TB<i>Detect’</i> microscopy in DMCs, sample preparation and testing, training, time-to-result, logistics, and troubleshooting. A scoring questionnaire was also used to assess ‘TB<i>Detect</i>’ microscopy <i>vs</i>. LED-FM and statistical significance of the scores was calculated using paired <i>t</i>-test. The overall positivity of ‘TB<i>Detect</i>’ microscopy was 10.32% (547/5300) <i>vs.</i> 8.96% (475/5300) of LED-FM at all sites and the increment in positivity was significant (<i>p</i> = 0.019). In addition, ‘TB<i>Detect</i>’ microscopy yielded an increment in smear grade status over LED-FM (<i>p</i> = 0.043). The feedback from the study-in-charge and kit users indicated that ‘TB<i>Detect</i>’ microscopy was easily adapted in point-of-care settings. An analysis of scoring feedback suggested that it was easy to perform and observe in comparison to LED-FM (<i>p</i> &lt; 0.005). This study established the feasibility of ‘TB<i>Detect</i>’ microscopy in field settings.印度目前主要依靠直接涂片显微镜检查（direct smear microscopy）开展结核病（tuberculosis, TB）诊断。然而，涂片镜检灵敏度偏低的短板凸显了提升其检测性能的迫切需求。我们此前已报道了"TB Detect"检测试剂盒的研发工作，该试剂在印度国家参考实验室（National Reference Laboratories, NRLs）中的检测性能优于直接涂片显微镜检查。本研究旨在评估"TB Detect"显微镜检测在现场环境中的应用可行性。本研究通过两项内容开展评估：(i) 针对布巴内斯瓦尔、博帕尔、金奈及新德里4家国家参考实验室下辖的13家指定显微镜检查中心（Designated Microscopy Centres, DMCs）接诊的5300例连续入组疑似肺结核患者，分别采用"TB Detect"显微镜检测与LED荧光显微镜检查（LED-fluorescence microscopy, LED-FM）开展比对，并评估其检测性能；(ii) 通过半结构化问卷（semi-structured questionnaires），向10名科研人员及42名实验室技术人员收集反馈，调研参数涵盖：指定显微镜检查中心开展"TB Detect"显微镜检测的可行性、样本制备与检测流程、培训要求、检测耗时、物流保障及问题排查。此外，研究还采用评分问卷对"TB Detect"显微镜检测与LED-FM进行对比评估，并通过配对t检验（paired t-test）计算评分的统计学显著性差异。所有受试位点中，"TB Detect"显微镜检测的总体阳性率为10.32%（547/5300），而LED-FM的阳性率为8.96%（475/5300），阳性率提升具有统计学显著性（p=0.019）。此外，相较于LED-FM，"TB Detect"显微镜检测可提升涂片分级结果的判定效能（p=0.043）。项目负责人及试剂盒使用者的反馈显示，"TB Detect"显微镜检测可轻松适配即时检测（point-of-care）场景。评分反馈分析结果表明，相较于LED-FM，"TB Detect"显微镜检测操作与结果判读更为简便（p<0.005）。本研究证实了"TB Detect"显微镜检测在现场环境中的应用可行性。