Assessing VirScan serosurvey epitope profiling variability between in-clinic venous blood draw and capillary blood self-sampling device

Timely and ongoing in-clinic sample collections are a common logistical barrier to volunteer participation and retention in longitudinal clinical studies. To remove this barrier, clinical studies have recently begun to implement the use of at-home capillary blood self-sampling devices in place of in-clinic venous blood draws for participant blood sample collection. Thus, we assessed antibody responses to a broad library of over 300 viral, bacterial, and fungal pathogens using VirScan immunoassay testing on adult volunteer capillary (serum) and venous (plasma) blood samples collected by Tasso devices and in-clinic venipunctures on the same day to determine whether self-sampling devices are a more practical and convenient alternative for future clinical studies. Most VirScan measurements of antibodies specific for clinically relevant respiratory viruses and herpesviruses had strong concordance between participant-matched Tasso and venipuncture blood samples. While we did not identify a systematic bias in most pathogen-specific antibody measurements associated with blood collection method, we did observe intrinsic VirScan inter-assay variability across some clinically relevant viruses. Together, our data demonstrate that capillary blood self-sampling devices are a practical alternative to in-clinic venipunctures for VirScan clinical research studies. However, these blood collection methods should not be used interchangeably within longitudinal studies to minimize the introduction of technical variables.IMPORTANCEOur study assessed whether capillary blood self-sampling devices could reliably replace in-clinic venous blood collection methods for the VirScan immunoassay, which can detect antibodies specific to hundreds of pathogens. Longitudinal studies requiring multiple in-clinic visits for sample collection often experience low volunteer retention because of the inconvenience of traveling to research sites. Allowing volunteers to use at-home self-sampling devices reduces the burden of travel for participants and increases access to outreach for volunteers who would otherwise not participate in research. Importantly, VirScan only requires a small sample volume, so blood self-sampling devices would be appropriate to use despite their volume collection limitations. Overall, capillary blood self-sampling devices can be a reliable and efficient method for research studies to investigate antibody responses longitudinally using VirScan. However, to limit the introduction of technical variables, collection methods should not be used interchangeably within a longitudinal study.