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Development of a high-throughput SARS-CoV-2 antibody testing pathway using dried blood spot specimens

2020; SAGE Publishing; Volume: 58; Issue: 2 Linguagem: Inglês

10.1177/0004563220981106

1758-1001

Stuart J. Moat, Wioleta M. Zelek, Emily Carne, Mark Ponsford, Kathryn Bramhall, Sara R. Jones, Tariq El‐Shanawany, Matt P. Wise, Annette Thomas, Chloë George, Chris Fegan, Rachael Steven, Russell Webb, Ian Weeks, B. Paul Morgan, Stephen Jolles,

Biosensors and Analytical Detection

Background Serological assays for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) have roles in seroepidemiology, convalescent plasma-testing, antibody durability and vaccine studies. Currently, SARS-CoV-2 serology is performed using serum/plasma collected by venepuncture. Dried blood spot (DBS) testing offers significant advantages as it is minimally invasive, avoids venepuncture with specimens being mailed to the laboratory. Methods A pathway utilizing a newborn screening laboratory infrastructure was developed using an enzyme-linked immunosorbent assay to detect IgG antibodies against the receptor-binding domain of the SARS-CoV-2 spike protein in DBS specimens. Paired plasma and DBS specimens from SARS-CoV-2 antibody-positive and -negative subjects and polymerase chain reaction positive subjects were tested. DBS specimen stability, effect of blood volume and punch location were also evaluated. Results DBS specimens from antibody-negative ( n = 85) and -positive ( n = 35) subjects and polymerase chain reaction positive subjects ( n = 11) had a mean (SD; range) optical density (OD) of 0.14 (0.046; 0.03–0.27), 0.98 (0.41; 0.31–1.64) and 1.12 (0.37; 0.49–1.54), respectively. An action value OD >0.28 correctly assigned all cases. The weighted Deming regression for comparison of the DBS and the plasma assay yielded: y = 0.004041 + 1.005 x, r = 0.991, Sy/ x 0.171, n = 82. Extraction efficiency of antibodies from DBS specimens was >99%. DBS specimens were stable for at least 28 days at ambient room temperature and humidity. Conclusions SARS-CoV-2 IgG receptor-binding domain antibodies can be reliably detected in DBS specimens. DBS serological testing offers lower costs than either point of care or serum/plasma assays that require patient travel, phlebotomy and hospital/clinic resources; the development of a DBS assay may be particularly important for resource poor settings.