Rapid SARS-CoV-2 testing with duplexed recombinase polymerase amplification and a bacteriophage internal control

ABSTRACT

OBJECTIVES/GOALS Current COVID-19 rapid molecular tests require cartridge-reader detection, expensive circuitry, and complex microfluidics making the most accurate tests unavailable to the masses. Here we present a rapid molecular diagnostic leveraging isothermal amplification and paper-based microfluidics for a low-cost ultra-sensitive COVID-19 assay. METHODS/STUDY POPULATION We designed a reverse transcription recombinase polymerase amplification (RT-RPA) assay for the detection of SARS-CoV-2 and bacteriophage MS2 RNA. RT-RPA is a sequence specific, ultrasensitive, rapid isothermal DNA amplification technique that is well suited to home based testing due to its rapid assay time, robustness, ease of use, and readout options. RT-RPA reagents are added to a tube and incubated at 39°C in a fluorometer. Realtime fluorometer data gives results in under 15 minutes. This assay also provides visual detection via lateral flow readout with results in 23 minutes. RESULTS/ANTICIPATED RESULTS: We have developed a rapid multiplexed nucleic acid amplification assay with an internal process control for SARS-CoV-2 using single-pot RT-RPA. We screened 21 primer combinations to select primers that demonstrated excellent performance and target specificity against common respiratory viruses. We demonstrate the ability to multiplex SARS-CoV-2 and MS2 detection, utilizing MS2 as an internal process control for lysis, reverse transcription, amplification, and readout. We show duplexed detection using both fluorescence readout and visual readout using lateral flow strips. Duplexed fluorescence detection shows a limit of detection of 25 copies per reaction. Duplexed lateral flow readout shows a limit of detection of 50 copies per reaction DISCUSSION/SIGNIFICANCE: We developed a duplexed RT-RPA assay for SARS-CoV-2 with fluorescence or lateral flow readout. Our assay does not re-quire expensive reader, circuity, or fluid handling. The low material cost, temperature, and robustness make it ideal for a more accurate home-based COVID-19 diagnostic.