Development and performance of a point-of-care rapid antigen test for detection of SARS-COV-2 variants

Background: SARS-CoV-2 antigen-based tests are well-calibrated to infectiousness and have a critical role to play in the COVID-19 public health response. We report the development and performance of a unique lateral flow immunoassay (LFA). Methods: Combinations of several monoclonal antibodies targeting multiple antigenic sites on the SARS-CoV-2 nucleocapsid protein (NP) were isolated, evaluated, and chosen for the development of a LFA termed CoV-SCAN (BioMedomics, Inc.). Clinical point-of-care studies in symptomatic and asymptomatic individuals were conducted to evaluate positive predictive agreement (PPA) and negative predictive agreement (NPA) with RT-PCR as comparator. Results: In laboratory testing, CoV-SCAN detected 14 recombinant N-proteins of SARS-CoV-2 variants with sensitivity in the range of 0.2–3.2 ng/mL, and 10 authentic SARS-CoV-2 variants with sensitivity in the range of 1.6–12.5 TCID50/swab. No cross reactivity was observed with other human coronaviruses or other respiratory pathogens. In clinical point-of-care testing on 148 individuals over age 2 with symptoms of ≤5 days, PPA was 87.2% (CI 95: 78.3–94.8%) and NPA was 100% (CI 95: 94.2–100%). In another 884 asymptomatic individuals, PPA was 85.7% (CI 95: 42.1–99.6%) and 99.7% (99.0–99.9%). Overall, CoV-SCAN detected over 97.2% of specimens with CT values