Department of Pathology and Laboratory Medicine, Division of Microbiology, Nova Scotia Health, Halifax, Nova Scotia, Canada.
Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.
Microbiol Spectr. 2022 Aug 31;10(4):e0063922. doi: 10.1128/spectrum.00639-22. Epub 2022 Jul 13.
Antigen-based rapid diagnostic tests (Ag-RDTs) have been widely used for the detection of SARS-CoV-2 during the coronavirus disease 2019 (COVID-19) pandemic. In settings of low disease prevalence, such as asymptomatic community testing, national guidelines recommend confirmation of positive Ag-RDT results with a nucleic acid amplification test (NAAT). This often requires patients to be recalled for repeat specimen recollection and subsequent testing in reference laboratories. This project assessed the use of a point-of-care molecular NAAT for SARS-CoV-2 detection (i.e., ID NOW), which was performed on-site at a volunteer-led asymptomatic community testing site on the residual test buffer (RTB) from positive Ag-RDTs. The ID NOW NAAT assay was performed on RTB from two Ag-RDTs: the Abbott Panbio and BTNX Rapid Response assays. Results of ID NOW were compared to real-time RT-PCR at a reference laboratory. Along with investigations into the clinical performance of ID NOW on RTB, analytical specificity was assessed with a panel of various respiratory organisms. Of the Ag-RDTs results evaluated, all 354 Ag-RDTs results characterized as true positives by RT-PCR were accurately identified with ID NOW testing of RTB. No SARS-CoV-2 detections by ID NOW were observed from 10 specimens characterized as false-positive Ag-RDTs, or from contrived specimens with various respiratory organisms. The use of on-site molecular testing on RTB provides a suitable option for rapid confirmatory testing of positive Ag-RDTs, thereby obviating the need for specimen recollection for molecular testing at local reference laboratories. During the COVID-19 pandemic, rapid antigen tests have been widely used for the detection of SARS-CoV-2. These simple devices allow rapid test results. However, false-positive results may occur. As such, individuals with positive rapid tests often must return to testing centers to have a second swab collected, which is then transported to a specialized laboratory for confirmation using molecular tests. As an alternative to requiring a repeat visit and a prolonged turn-around time for result confirmation, this project evaluated whether the leftover material from rapid antigen tests could be confirmed directly on a portable point-of-care molecular instrument. Using this approach, molecular confirmation of positive antigen tests could be performed in less than 15 min, and the results were equivalent to laboratory-based confirmation. This procedure eliminates the need for individuals to return to testing centers following a positive rapid antigen test and ensures accurate antigen test results through on-site confirmation.
基于抗原的快速诊断检测 (Ag-RDT) 在 2019 年冠状病毒病 (COVID-19) 大流行期间已被广泛用于 SARS-CoV-2 的检测。在疾病流行率较低的情况下，例如无症状社区检测，国家指南建议用核酸扩增检测 (NAAT) 确认阳性 Ag-RDT 结果。这通常需要患者被召回以重复采集样本，并在参考实验室进行后续检测。本项目评估了一种即时分子 NAAT 用于 SARS-CoV-2 检测 (即 ID NOW) 的使用情况，该方法在志愿者主导的无症状社区检测点，对阳性 Ag-RDT 的剩余测试缓冲液 (RTB) 进行现场检测。ID NOW NAAT 检测在两种 Ag-RDT 的 RTB 上进行：雅培 Panbio 和 BTNX 快速反应检测。ID NOW 的结果与参考实验室的实时 RT-PCR 进行比较。除了对 ID NOW 在 RTB 上的临床性能进行研究外，还使用各种呼吸道病原体的面板评估了分析特异性。在评估的 Ag-RDT 结果中，通过 ID NOW 检测 RTB，准确识别了所有 354 个 RT-PCR 确定为真阳性的 Ag-RDT 结果。从 10 个特征为假阳性 Ag-RDT 的样本或含有各种呼吸道病原体的人工样本中，均未观察到 ID NOW 检测到 SARS-CoV-2。在 RTB 上进行现场分子检测为快速确认阳性 Ag-RDT 提供了一个合适的选择，从而避免了在当地参考实验室采集样本进行分子检测的需要。在 COVID-19 大流行期间，快速抗原检测已被广泛用于 SARS-CoV-2 的检测。这些简单的设备可以快速得到检测结果。然而，可能会出现假阳性结果。因此，阳性快速检测结果的个体通常必须返回检测中心采集第二个拭子，然后将其运送到专门的实验室进行分子检测确认。为了替代需要重复访问和延长结果确认时间，本项目评估了是否可以直接在便携式即时分子仪器上对快速抗原检测的剩余材料进行确认。使用这种方法，阳性抗原检测的分子确认可以在不到 15 分钟内完成，并且结果与实验室确认结果相当。该程序消除了个体在快速抗原检测阳性后返回检测中心的需要，并通过现场确认确保了准确的抗原检测结果。
