PLoS ONE (Jan 2021)

Dried blood spot specimens for SARS-CoV-2 antibody testing: A multi-site, multi-assay comparison.

  • François Cholette,
  • Christine Mesa,
  • Angela Harris,
  • Hannah Ellis,
  • Karla Cachero,
  • Philip Lacap,
  • Yannick Galipeau,
  • Marc-André Langlois,
  • Anne-Claude Gingras,
  • Cedric P Yansouni,
  • Jesse Papenburg,
  • Matthew P Cheng,
  • Pranesh Chakraborty,
  • Derek R Stein,
  • Paul Van Caeseele,
  • Sofia Bartlett,
  • Mel Krajden,
  • David Goldfarb,
  • Allison McGeer,
  • Carla Osiowy,
  • Catherine Hankins,
  • Bruce Mazer,
  • Michael Drebot,
  • John Kim,
  • COVID-19 Immunity Task Force (CITF) working group

DOI
https://doi.org/10.1371/journal.pone.0261003
Journal volume & issue
Vol. 16, no. 12
p. e0261003

Abstract

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The true severity of infection due to COVID-19 is under-represented because it is based on only those who are tested. Although nucleic acid amplifications tests (NAAT) are the gold standard for COVID-19 diagnostic testing, serological assays provide better population-level SARS-CoV-2 prevalence estimates. Implementing large sero-surveys present several logistical challenges within Canada due its unique geography including rural and remote communities. Dried blood spot (DBS) sampling is a practical solution but comparative performance data on SARS-CoV-2 serological tests using DBS is currently lacking. Here we present test performance data from a well-characterized SARS-CoV-2 DBS panel sent to laboratories across Canada representing 10 commercial and 2 in-house developed tests for SARS-CoV-2 antibodies. Three commercial assays identified all positive and negative DBS correctly corresponding to a sensitivity, specificity, positive predictive value, and negative predictive value of 100% (95% CI = 72.2, 100). Two in-house assays also performed equally well. In contrast, several commercial assays could not achieve a sensitivity greater than 40% or a negative predictive value greater than 60%. Our findings represent the foundation for future validation studies on DBS specimens that will play a central role in strengthening Canada's public health policy in response to COVID-19.