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Dried blood spot specimens for SARS-CoV-2 antibody testing: A multi-site, multi-assay comparison
François Cholette1,2, Christine Mesa1, Angela Harris1
1National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, Canada.
Plos One
|December 7, 2021
Summary
Dried blood spot (DBS) testing offers a practical solution for large-scale SARS-CoV-2 seroprevalence surveys in Canada. Some commercial and in-house assays demonstrated 100% accuracy, while others showed poor performance.
Area of Science:
- Immunology
- Public Health
- Infectious Diseases
Background:
- COVID-19 severity is underestimated due to limited testing.
- Nucleic acid amplification tests (NAAT) are standard for diagnosis, but serological assays better estimate population prevalence.
- Canada's geography presents challenges for large sero-surveys.
Purpose of the Study:
- To evaluate the performance of SARS-CoV-2 antibody tests using dried blood spot (DBS) samples.
- To provide comparative data for selecting appropriate serological assays for Canadian sero-surveys.
Main Methods:
- A well-characterized SARS-CoV-2 DBS panel was distributed to laboratories across Canada.
- Twelve SARS-CoV-2 antibody tests (10 commercial, 2 in-house) were evaluated.
- Test performance metrics including sensitivity, specificity, and predictive values were assessed.
Main Results:
- Three commercial assays and two in-house assays achieved 100% sensitivity, specificity, and predictive values.
- Several commercial assays exhibited low sensitivity (<40%) and negative predictive values (<60%).
Conclusions:
- Dried blood spot sampling is a viable method for SARS-CoV-2 serosurveys in Canada.
- Validated DBS assays are crucial for accurate population-level COVID-19 prevalence estimation.
- Findings will inform future validation studies and Canadian public health policy.
