Shan, DandanLatz, EickeBall, Andrew J.2022-08-232022-08-232020-08-282020-09-03<p>medRxiv 2020.08.14.20175356; doi: https://doi.org/10.1101/2020.08.14.20175356. <a href="https://doi.org/10.1101/2020.08.14.20175356" target="_blank" title="View preprint on medRxiv">Link to preprint on medRxiv service</a></p>10.1101/2020.08.14.20175356https://hdl.handle.net/20.500.14038/29543<p>Full author list omitted for brevity. For the full list of authors, see article.</p>The COVID-19 pandemic continues to have an unprecedented impact on societies and economies worldwide. Despite rapid advances in diagnostic test development and scale-up, there remains an ongoing need for SARS-CoV-2 tests which are highly sensitive, specific, minimally invasive, cost-effective and scalable for broad testing and surveillance. Here we report development of a highly sensitive single molecule array (Simoa) immunoassay on the automated HD-X platform for the detection of SARS-CoV-2 Nucleocapsid protein (N-protein) in venous and capillary blood (fingerstick). In pre-pandemic and clinical sample sets, the assay has 100% specificity and 97.4% sensitivity for serum / plasma samples. The limit of detection (LoD) estimated by titration of inactivated SARS-CoV-2 virus is 0.2 pg/ml, corresponding to 0.05 Median Tissue Culture Infectious Dose (TCID50) per ml, > 2000 times more sensitive than current EUA approved antigen tests. No cross-reactivity to other common respiratory viruses, including hCoV229E, hCoVOC43, hCoVNL63, Influenza A or Influenza B, was observed. We detected elevated N-protein concentrations in symptomatic, asymptomatic, and pre-symptomatic PCR+ individuals using capillary blood from a finger-stick collection device. The Simoa SARS-CoV-2 N-protein assay has the potential to detect COVID-19 infection via antigen in blood with similar or better performance characteristics of molecular tests, while also enabling at home and point of care sample collection.en-USThe copyright holder for this preprint (which was not peer-reviewed) is the author/funder. It is made available under a CC-BY-NC 4.0 International license.http://creativecommons.org/licenses/by-nc/4.0/Infectious DiseasesSimoa ultra-sensitive immunoassayCOVID-19testingprotein assayImmunology of Infectious DiseaseImmunopathologyInfectious DiseaseVirus DiseasesPreprinthttps://escholarship.umassmed.edu/cgi/viewcontent.cgi?article=2794&amp;context=faculty_pubs&amp;unstamped=1https://escholarship.umassmed.edu/faculty_pubs/176519233813faculty_pubs/1765