Clinical Performance of Three Commercial and Two In-House Multiplex Assays for SARS-CoV-2 Antibody Detection in Dried Blood Spot Specimens

The extent of the COVID-19 pandemic will be better understood through serosurveys and SARS-CoV-2 antibody testing. Dried blood spot (DBS) samples will play a central role in large scale serosurveillance by simplifying biological specimen collection and transportation, especially in Canada. Direct comparative clinical performance data on multiplex SARS-CoV-2 assays resulting from identical DBS samples are currently lacking. In our study, we aimed to provide clinical performance data for the BioPlex 2200 SARS-CoV-2 IgG (Bio-Rad), V-PLEX SARS-CoV-2 Panel 2 IgG (MSD), and Elecsys Anti-SARS-CoV-2 (Roche) commercial assays, as well as for two highly scalable in-house assays (University of Ottawa and Mount Sinai Hospital protocols) to assess their suitability for DBS-based SARS-CoV-2 DBS serosurveillance. These assays were evaluated against identical panels of DBS samples collected from convalescent COVID-19 patients (n =97) and individuals undergoing routine sexually transmitted and bloodborne infection (STBBI) testing prior to the COVID-19 pandemic (n =90). Our findings suggest that several assays are suitable for serosurveillance (sensitivity >97% and specificity >98%) even in low prevalence settings. In contrast to other reports, we did not observe an improvement in clinical performance using multiple antigen consensus-based rules to establish overall seropositivity. This may be due to our DBS panel which consisted of samples collected from convalescent COVID-19 patients with significant anti-spike, -RBD, and nucleocapsid antibody titers. This study demonstrates that biological specimens collected as DBS coupled with one of several readily available assays are useful for large-scale COVID-19 serosurveillance nonetheless.

Funding Information:Marc-Andre ́ Langlois (M.-A.L.) holds a Canada Research Chair in Molecular Virology and Intrinsic Immunity. This study was supported in part by a COVID-19 Rapid Response grant to M.-A. L. by the Canadian Institute of Health Research (CIHR; OV1-170355) and by a grant supplement by the COVID-19 Immunity Task Force (CITF). The authors did not receive a salary from any of the funders.

Conflict of Interests:The authors have declared that no competing interests exist.

Ethical Approval: ll experiments were carried out in accordance with relevant guidelines and regulations. Written informed consent was obtained from all participants who provided blood samples. All participants were 18 years of age or older. Ethical approval was obtained from the Health Canada and Public Health Agency of Canada Research Ethics Board (no. 2020-022P).

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Cholette, Francois and Fabia, Rissa and Harris, Angela and Ellis, Hannah and Cachero, Karla and Schroeder, Lukas and Mesa, Christine and Lacap, Philip and Arnold, Corey and Galipeau, Yannick and Langlois, Marc-André and Colwill, Karen and Colwill, Karen and Gingras, Anne-Claude and McGeer, Allison and Giles, Elizabeth and Day, Jacqueline and Osiowy, Carla and Durocher, Yves and Hankins, Catherine and Mazer, Bruce D. and Drebot, Michael and Kim, John, Clinical Performance of Three Commercial and Two In-House Multiplex Assays for SARS-CoV-2 Antibody Detection in Dried Blood Spot Specimens. Available at SSRN: https://ssrn.com/abstract=4057604 or http://dx.doi.org/10.2139/ssrn.4057604

This version of the paper has not been formally peer reviewed.