The COVID-19 pandemic provides an urgent example where a gap exists between availability of state-of-the-art diagnostics and current needs. As assay protocols and primer sequences become widely known, many laboratories perform diagnostic tests using methods such as RT-PCR or reverse transcription loop mediated isothermal amplification (RT-LAMP). Here, we report an RT-LAMP isothermal assay for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus and demonstrate the assay on clinical samples using a simple and accessible point-of-care (POC) instrument. We characterized the assay by dipping swabs into synthetic nasal fluid spiked with the virus, moving the swab to viral transport medium (VTM), and sampling a volume of the VTM to perform the RT-LAMP assay without an RNA extraction kit. The assay has a limit of detection (LOD) of 50 RNA copies per μL in the VTM solution within 30 min. We further demonstrate our assay by detecting SARS-CoV-2 viruses from 20 clinical samples. Finally, we demonstrate a portable and real-time POC device to detect SARS-CoV-2 from VTM samples using an additively manufactured three-dimensional cartridge and a smartphone-based reader. The POC system was tested using 10 clinical samples, and was able to detect SARS-CoV-2 from these clinical samples by distinguishing positive samples from negative samples after 30 min. The POC tests are in complete agreement with RT-PCR controls. This work demonstrates an alternative pathway for SARS-CoV-2 diagnostics that does not require conventional laboratory infrastructure, in settings where diagnosis is required at the point of sample collection.

COVID-19 大流行提供了一个紧迫的例子，表明最先进的诊断方法与当前需求之间存在差距。随着检测方案和引物序列广为人知，许多实验室使用 RT-PCR 或逆转录环介导等温扩增 (RT-LAMP) 等方法进行诊断测试。在此，我们报告了一种用于检测严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 病毒的 RT-LAMP 等温测定，并使用简单且易于使用的护理点 (POC) 仪器在临床样本上演示了该测定。我们通过将拭子浸入掺有病毒的合成鼻液中，将拭子移至病毒转运介质 (VTM) 中，并对 VTM 进行采样，在不使用 RNA 提取试剂盒的情况下进行 RT-LAMP 测定，从而对测定进行表征。该测定的检测限 (LOD) 为 30 分钟内 VTM 溶液中每 μL 50 个 RNA 拷贝。我们通过检测 20 个临床样本中的 SARS-CoV-2 病毒来进一步证明我们的检测方法。最后，我们展示了一种便携式实时 POC 设备，可使用增材制造的三维墨盒和基于智能手机的读取器从 VTM 样本中检测 SARS-CoV-2。 POC系统使用10个临床样本进行测试，30分钟后通过区分阳性样本和阴性样本，能够从这些临床样本中检测出SARS-CoV-2。 POC 测试与 RT-PCR 对照完全一致。这项工作展示了 SARS-CoV-2 诊断的替代途径，在样本采集时需要诊断的环境中，不需要传统的实验室基础设施。