Dried blood spots are useful sero-surveillance tools for detecting COVID-19 infection in populations hard to reach.
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Validation of commercially available assays for the detection of SARS-CoV-2 antibodies using dried blood spots.
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Assays targeting spike protein demonstrate superior diagnostic accuracy.
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First dried blood spot validation of Binding SiteTM anti-IgG/A/M spike protein ELISA.
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Dried blood spots suitable to facilitate post vaccination monitoring.
Abstract
Background
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.
Objectives
To compare detection of naturally acquired SARS-CoV-2 antibodies in paired DBS and serum specimens using commercially available serological immunoassays.
Study Design
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.
Results
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.
Conclusions
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).
Keywords
Dried blood spots
DBS
SARS-CoV-2
COVID-19
Surveillance
Diagnostics
Cited by (0)
The authors confirm that this manuscript has not been published previously and is not currently being considered for publication elsewhere.
Previously presented: Interim findings from this research have been presented in a WHO report.
Person to address for correspondence and request for reprint: Mitchell Starr, St Vincent's Centre for Applied Medical Research, St Vincent's Hospital, Sydney, New South Wales, Australia, Phone: +61-2-8382-4942, Fax: +61-2-8382-4249.
