Detection of SARS-CoV-2 antibodies using an innovative approach: dried blood spots offer the possibility of home-based self-collection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to be an international public health emergency due to rapid human-to-human transmission, emergence of new variants, high prevalence of asymptomatic carriers, and reduction of social distancing measures. While vaccination establishes protection through a combination of cell-mediated immunity and production of neutralizing antibodies, the longevity of circulating antibody against SARS-CoV-2 is relatively short, and the level of antibody needed to establish protection cutoffs has not yet been determined. Despite this, antibody levels continue to be used as the surrogate marker for exposure to SARS-CoV-2 through both vaccination and natural infection, and have successfully been used to inform public health responses. Serological measurements are typically performed using serum or plasma samples obtained intravenously; however, dried blood spot (DBS) samples offer an innovative approach of sample collection with several advantages over traditional phlebotomy. In addition to utilizing a smaller volume of blood (~75 µL of blood/spot) and less stringent shipping requirements, DBS cards can be successfully collected in point of care settings with minimal training. Here we describe the ability to measure SARS-CoV-2 antibodies from DBS samples using the LIAISON SARS-CoV-2 TrimericS IgG immunoassay, for measurement of antibodies in whole blood compared to traditional venous serum and plasma samples. The feasibility of using this assay to measure SARS-CoV-2 antibodies has been demonstrated in many international publications, however, further investigation including studies based on regulatory guidance is required prior to utilization of DBS samples for at-home self-collection.

 

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