Highly sensitive detection of SARS-CoV-2 RNA by multiplex rRT-PCR for molecular diagnosis of COVID-19 by clinical laboratories

Ishige, Takayuki; Murata, Shota; Taniguchi, Toshibumi; Miyabe, Akiko; Kitamura, Kouichi; Kawasaki, Kenji; Nishimura, Motoi; Igari, Hidetoshi; Matsushita, Kazuyuki

Abstract Background The detection of SARS-CoV-2 RNA by real-time reverse transcription–polymerase chain reaction (rRT-PCR) is used to confirm the clinical diagnosis of COVID-19 by molecular diagnostic laboratories. We developed a multiplex rRT-PCR methodology for the detection of SARS-CoV-2 RNA. Methods Three genes were used for multiplex rRT-PCR: the Sarbecovirus specific E gene, the SARS-CoV-2 specific N gene, and the human ABL1 gene as an internal control. Results Good correlation of Cq values was observed between the simplex and multiplex rRT-PCR methodologies. Low copies (<25 copies/reaction) of SARS-CoV-2 RNA were detected by the novel multiplex rRT-PCR method. Conclusion The proposed multiplex rRT-PCR methodology will enable highly sensitive detection of SARS-CoV-2 RNA, reducing reagent use and cost, and time required by clinical laboratory technicians.