A rapid water bath PCR combined with lateral flow assay for the simultaneous detection of SARS-CoV-2 and influenza B virus.

The outbreak of the coronavirus disease 2019 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in significant global health and economic threats to the human society. Thus, a rapid and accurate detection method for early testing and diagnosis should be established. In this study, a rapid water bath polymerase chain reaction (PCR) combined with lateral flow assay was developed to detect SARS-CoV-2 and influenza B virus simultaneously. A homemade automated transfer device equipped with reaction tube shuttled rapidly between two water baths at 98 °C and 53 °C to realize rapid PCR. After amplification, two-ended labeled PCR products were detected using the lateral flow strip with two test lines and streptavidin-conjugated quantum dot nanobeads. The fluorescence value was read using a handheld instrument. The established assay could complete reverse-transcription PCR amplification and lateral flow detection in 45 minutes. The detection limits were 8.44 copies per μL and 14.23 copies per μL for SARS-CoV-2 and influenza B virus, respectively. The coefficients of variation of the test strip were 10.10% for the SARS-CoV-2 and 4.94% for the influenza B virus, demonstrating the excellent repeatability of the experiment. These results indicated that the rapid PCR combined with lateral flow assay could detect SARS-CoV-2 and influenza B virus simultaneously at a short assay time and low cost, thereby showing the remarkable potential for the rapid and multiplex detection of respiratory viruses in resource-limited settings.