Comparing Participant Experiences of at-Home and Hospital-Based Biological Sampling: Cross-Sectional Insights From the SIREN Study.

Engaging and retaining research participants in studies that require sampling (e.g., blood, sputum) can be challenging. Regularly contributing biological sampling can be demanding for healthcare workers (HCW) in particular. SIREN is a prospective cohort of HCW in the UK who have been carrying out COVID-19 testing since 2020. We aimed to evaluate satisfaction with at-home PCR and blood sampling by collecting SIREN participants' feedback regarding sampling processes for COVID-19 testing. We explored the acceptability of at-home (PCR swab and finger-prick blood sampling) compared to at-hospital (PCR swab and phlebotomy) sampling. Thematic analysis was used to code free-text responses. Out of 2,816 respondents, 74% preferred PCR testing at home compared to on site. Half of 1,279 participants who returned blood samples using a postal kit preferred to complete serological sampling at home instead of in hospital (52%). One in five reported no preference. Participants valued the ease and convenience of home-sampling and clear communication about instructions and test results. Some participants reported difficulties with blood collection or logistic issues related to kits, but this did not prevent them from returning samples nor deter them from undergoing sampling in future research. Home-sampling for PCR and serological testing was acceptable and feasible in this HCW cohort. Self-sampling can be a cost-effective and efficient way of collecting participant data. Clear communications about instructions for sample collection and the purpose of capturing the sample, easy-to-use devices and ensuring participants feel valued are strong facilitators to high uptake, and on-going study retention.