Analytical sensitivity of six lateral flow antigen test kits for variant strains of SARS-CoV-2

Abstract

IntroductionThe lateral flow antigen test is a useful tool for rapid diagnosis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The analytical sensitivity of six lateral flow antigen test kits was compared. MethodsThe limit of detection (LoD) and time to positive results were evaluated for six lateral flow tests including ImmunoArrow®, ESPLINE® SARS-CoV-2, QuickNavi™ COVID19 Ag, ImmunoAce® SARS-CoV-2, Panbio™ COVID-19 Ag Rapid Test Device, and SARS-CoV-2 Rapid Antigen Test using the heat-inactivated virus. The LoD of ImmunoArrow® against the Omicron variants was compared with that against the wild-type using recombinant proteins. ResultsImmunoArrow® and ESPLINE® showed the lowest LoD. The time to positive results of all tests except for ESPLINE® was within 200 s in the evaluation at high dose of antigens (2.5 × 105 TCID50/mL) and 500 s in the evaluation at low dose of antigens (2.5 × 104 TCID50/mL). The LoD of ImmunoArrow® against the Omicron variants was the same concentration against the wild-type antigen. ConclusionsImmunoArrow® detected SARS-CoV-2 antigens including the Omicron variants with good sensitivity among the six lateral flow antigen tests. These finding support that it can support the rapid diagnosis of COVID-19 with the good sensitivity.