Development of an Accurate and Rapid Antigen Assay for COVID-19 Diagnostics Using Saliva

The global outbreak of COVID-19 highlighted the need for rapid and accurate diagnostic testing to control the spread of this highly contagious disease (1-5). Here, we describe the nCoVega COVID-19 antigen rapid test (~ 15min) that can detect the presence of the SARS-COV-2 virus particles from saliva sample on a portable device. The portable reader instrument, the Vega-200, has a small footprint and is designed for use at point of care settings. The test detects the fluorescence signal using wide-field illumination from antigen-antibody complexes captured on a special filter matrix (6). Results of this clinical evaluation of 183 subjects demonstrates that the nCoVega COVID-19 test performs at par with qRT-PCR tests (7) (gold standard) for both symptomatic and asymptomatic patients with a strong inverse correlation between RFU (relative fluorescence units) and Ct counts (from RT-PCR). Based on a recently-filed EUA application with the FDA, the test has an analytical performance of 15.3 TCID50/mL, and 100% specificity for COVID-19 as compared to other human respiratory viruses, including other human coronaviruses. The test has recently been CE-approved. The working principle of this assay and test system can be used for developing other rapid, inexpensive antigen assays and it can offer an end-to-end, point-of-care solution to meet the continuous demand in tackling existing and emerging infectious diseases across the globe.