Development of an immunochromatographic kit to detect severe acute respiratory syndrome coronavirus 2

Abstract

\n Background\n The novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for the worldwide coronavirus disease-19 (COVID-19) pandemic, starting in late 2019. The standard diagnostic methods to detect SARS-CoV-2 are PCR-based genetic assays. Antigen-antibody-based immunochromatographic assays are alternative methods of detecting this virus. Rapid diagnosis kits to detect SARS-CoV-2 are urgently needed.\n \n Study design\n Three monoclonal antibodies against SARS-CoV-2 nucleocapsid (N) protein were used to develop an antigen-antibody-based immunochromatographic kit to detect SARS-CoV-2. These assays were evaluated using\u3000 nasopharyngeal swab specimens collected from patients suspected of having COVID-19.\n \n Results\n These assays detected recombinant SARS-CoV-2\u2009N protein at concentrations >0.2\u2009ng/ml within 10\u2009minutes after protein loading, but did not detect the N proteins of Middle East respiratory syndrome coronavirus (MERS-CoV), human coronaviruses OC43 (HCoV-OC43) and 299E (HCoV-229E) and other pathogens causing respiratory infections. Nasopharyngeal swab specimens obtained 1～3, 4～9, and ≥ 10 days after symptom onset from COVID-19 patients diagnosed by RT-PCR showed positivity rates of 100%, >80%, and <30%, respectively.\n \n Conclusions\n Kits using this immunochromatographic assay may be a rapid and useful tool for point-of-care diagnosis of COVID-19 when samples are obtained from patients 1～9 days after symptom onset.\n