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Rapid and accurate agglutination-based testing for SARS-CoV-2 antibodies
Sally Esmail1, Michael J Knauer2, Husam Abdoh2
1Departments of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON N6G 2V4, Canada.
Cell Reports Methods
|July 8, 2021
Summary
A new latex particle agglutination test accurately detects SARS-CoV-2 antibodies. This rapid, cost-effective COVID-19 serologic test shows high sensitivity and specificity, potentially identifying neutralizing antibodies.
Area of Science:
- Immunology
- Virology
- Diagnostic Medicine
Background:
- The COVID-19 pandemic, caused by the SARS-CoV-2 virus, necessitates reliable diagnostic tools.
- Serologic tests are crucial for identifying past or present infections and assessing immune response.
- Existing diagnostic methods may have limitations in speed, cost, or accessibility.
Purpose of the Study:
- To develop and validate a rapid, accurate, and cost-effective serologic test for SARS-CoV-2 antibodies.
- To assess the correlation between antibody levels detected by the new assay and virus-neutralizing capacity.
- To evaluate the potential of the assay as a complementary diagnostic tool for SARS-CoV-2 infection.
Main Methods:
- Development of an antibody-dependent agglutination assay using antigen-coated latex particles.
- Validation of the assay with plasma samples confirmed positive or negative for SARS-CoV-2.
- Correlation analysis with a surrogate neutralization assay measuring the efficiency of plasma in blocking SARS-CoV-2 binding to ACE2.
Main Results:
- The agglutination assay demonstrated 100% specificity and approximately 98% sensitivity in detecting antibodies against SARS-CoV-2 spike (S-RBD) and nucleocapsid proteins.
- A strong correlation was observed between the S-RBD antibody response measured by agglutination and the plasma's virus-neutralizing efficiency.
- Over 92% of patients showed detectable antibodies on the day of a positive viral RNA test.
Conclusions:
- The developed latex agglutination assay is a highly sensitive and specific method for detecting SARS-CoV-2 antibodies.
- This serologic test may serve as a valuable tool for identifying individuals with virus-neutralizing antibodies.
- The agglutination antibody test can complement viral RNA testing for improved SARS-CoV-2 diagnosis.
