Sample-to-Answer and Routine Real-Time Reverse Transcription PCR (rRT-PCR): A Comparison of Different Platforms for SARS-CoV-2 Detection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is spreading all over the world and has causes millions of deaths. Several Sample-to-Answer platforms, including Cepheid Xpert Xpress SARS-CoV-2 (Xpert Xpress), have received emergency use authorization (EUA) for SARS-CoV-2 nucleic acid detection as a point of care test in the US. But their application niche is unclear comparing with real-time reverse transcription PCR (rRT-PCR) assays cleared by the National Medical Products Administration (NMPA) in China. In this study, the clinical performance, sensitivity and workflow of Xpert Xpress and two rRT-PCR kits (BioGerm, Shanghai and Sansure, Hunan) from 86 symptomatic patients were evaluated. The positive percent agreement (PPA) of Xpert Xpress was 100%, followed by BioGerm Kit (96.15%) and Sansure Kit (90%), respectively. The negative percent agreement (NPA) was 100% for three assays. The LoD is 100 copies/mL for Xpert Xpress, 500 copies/mL for BioGerm Kit and Sansure Kit. By serially diluting five positive specimens assay, the Xpert Xpress displayed better detection capability. In the workflow and throughput analysis, the turnaround time was 51 min for Xpert Xpress, 150 min for BioGerm kit and 210 min for Sansure kit. This study provides some indication for diagnosis methods selection.