Rapid and accurate agglutination-based testing for SARS-CoV-2 antibodies

Authors

Sally Esmail, Schulich School of Medicine & Dentistry
Michael J. Knauer, London Health Sciences Centre
Husam Abdoh, London Health Sciences Centre
Courtney Voss, Schulich School of Medicine & Dentistry
Benjamin Chin-Yee, London Health Sciences Centre
Peter Stogios, University of Toronto
Almagul Seitova, University of Toronto
Ashley Hutchinson, University of Toronto
Farhad Shah, Mount Sinai Hospital of University of Toronto
Cindy Dribnenki, Alberta Health Services
Joanne Snider, Alberta Health Services
Derek Stephens, Hospital for Sick Children University of Toronto

Document Type

Article

Publication Date

6-21-2021

Journal

Cell Reports Methods

Volume

1

Issue

2

URL with Digital Object Identifier

10.1016/j.crmeth.2021.100011

Abstract

We have developed a rapid, accurate, and cost-effective serologic test for SARS-CoV-2 virus, which caused the COVID-19 pandemic, on the basis of antibody-dependent agglutination of antigen-coated latex particles. When validated using plasma samples that are positive or negative for SARS-CoV-2, the agglutination assay detected antibodies against the receptor-binding domain of the spike (S-RBD) or the nucleocapsid protein of SARS-CoV-2 with 100% specificity and ∼98% sensitivity. Furthermore, we found that the strength of the S-RBD antibody response measured by the agglutination assay correlated with the efficiency of the plasma in blocking RBD binding to the angiotensin-converting enzyme 2 in a surrogate neutralization assay, suggesting that the agglutination assay might be used to identify individuals with virus-neutralizing antibodies. Intriguingly, we found that >92% of patients had detectable antibodies on the day of a positive viral RNA test, suggesting that the agglutination antibody test might complement RNA testing for the diagnosis of SARS-CoV-2 infection.