Evaluation of serological assays for SARS-CoV-2 antibody testing from dried blood spots collected from cohorts with prior SARS-CoV-2 infection

• Published in: Journal of clinical virology plus Vol. 2; no. 3; p. 100093
• Main Authors: Catlett, Beth, Starr, Mitchell, Machalek, Dorothy A, Danwilai, Thidarat, Palmer, Michael, Kelly, Andrew, Kaldor, John, Dore, Gregory J, Darley, David, Matthews, Gail, Cunningham, Philip H.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2022; The Authors. Published by Elsevier Ltd; Elsevier
• Subjects: COVID-19; DBS; Diagnostics; Dried blood spots; SARS-CoV-2; Surveillance; COVID-19; SARS-CoV-2; DBS; Surveillance; Diagnostics; Dried blood spots
• ISSN: 2667-0380; 2667-0380
• DOI: 10.1016/j.jcvp.2022.100093

•Dried blood spots are useful sero-surveillance tools for detecting COVID-19 infection in populations hard to reach.•Validation of commercially available assays for the detection of SARS-CoV-2 antibodies using dried blood spots.•Assays targeting spike protein demonstrate superior diagnostic accuracy.•First dried blood spot validation of Binding SiteTM anti-IgG/A/M spike protein ELISA.•Dried blood spots suitable to facilitate post vaccination monitoring. Dried blood spot (DBS) specimens are a useful serosurveillance tool particularly in hard-to-reach populations but their application for detecting SARS-CoV-2 infection is poorly characterised. To compare detection of naturally acquired SARS-CoV-2 antibodies in paired DBS and serum specimens using commercially available serological immunoassays. Specimens were collected through St Vincent's Hospital observational post COVID-19 cohort study (ADAPT). Laboratory spotted DBS from venepuncture were initially tested on seven assays, a DBS validation completed on three with clinically collected fingerstick DBSs tested on one. Sensitivity for Euroimmun nucleocapsid (NCP) IgG ELISA from laboratory spotted DBS (n=145), Euroimmun spike, IgG ELISA from laboratory spotted DBS (n=161), and Binding Site total antibody ELISA from clinically collected fingerstick DBS (n=391) was 100% (95% CI: 95.8-100%), 100% (95% CI: 95.8-100%) and 92.9% (95% CI: 89.5-95.5%), respectively. Specificity was 66.2% (95% CI: 53.6-77.0%), 96% (95% CI: 88.7-99.1%) and 98.8% (95% CI: 93.3-99.9%), respectively. All three assays’ results displayed a strong positive correlation between DBS compared to paired serum. The Binding Site™ spike total antibody and Euroimmun™ spike IgG ELISAs provided good analytical performance, demonstrating that DBS specimens could facilitate specimen collection in the epidemiological surveillance of SARS-CoV-2 infection. This is highly applicable in populations and settings where venepuncture is problematic (including community based regional/remote settings, nursing homes, prisons, and schools).