Serological detection of SARS-CoV-2 IgG using a commercially available enzyme immunoassays on dried blood spots collected from patients

Walker, G. J.; Davis, R.; Naing, Z.; McEntee, B.; Lu, Y.; Denadija, T.; Rawlinson, W. D.

Serological testing for SARS-CoV-2 antibodies provides important research and diagnostic information relating to COVID-19 immune response and surveillance. A major challenge when addressing protection post- infection or vaccination is the difficulty of specimen collection from infants and children. Dried blood spots (DBS) collected by finger prick or heel prick are a minimally invasive sample collection alternative previously used to detect antibodies to other viruses. In this study we evaluated DBS for the detection of SARS-CoV-2 antibodies on three commercially available enzyme (EIA) and chemiluminescent (CLIA) immunoassays by analysing paired DBS and serum samples collected from 54 subjects. We demonstrate that testing of DBS samples was highly sensitive and specific, and quantitative results strongly correlated with those of paired serum. These results suggest that DBS derived blood is a viable alternative to plasma or serum for use in EIAs and CLIAs, and has particular utility as a minimally invasive collection tool for COVID-19 serological testing of infants and children.