Safety and protection of plasma donors: A scoping review and evidence (gap) map

Background and objectives As part of a large-scale European project aiming to safely increase plasma collection in Europe, the current scoping review identifies the existing evidence (gaps) on adverse events (AEs) and other health effects in plasmapheresis donors, as well as factors that may be associated with such events/effects. Materials and methods We searched 6 databases and 3 registries. Study characteristics (publication type and language, study design, population, outcomes, associated factors, time of assessment, duration of follow-up, number and frequency of donations within the study period, convalescent plasma (y/n), study setting, and location) were charted in duplicate and in consultation with a content expert group. Results were synthesized narratively and in an interactive evidence gap map (EGM). Results Ninety-four research articles and 5 registrations focused on AEs (n = 38) and/or other health effects (n = 77) in plasmapheresis donors. Around 90% were observational studies (57 controlled; 33 uncontrolled), and most of them were performed in Europe (55%) or the USA (20%). Factors studied in association with donor health included donor characteristics (e.g., sex, age) (n = 27), cumulative number of donations (n = 21), donation frequency (n = 11), plasma collection device or program (n = 11), donor status (first-time versus repeat) (n = 10), donation volume per session (n = 8), time in donation program (n = 3), preventive measures (n = 2), or other (n = 9). Conclusion The current scoping review and EGM provide accessible tools for researchers and policy-makers to identify the available evidence and existing research gaps concerning plasmapheresis donation safety. Controlled, prospective studies with long-term donor follow-up are scarce. Furthermore, additional experimental studies comparing the health effects of different donation frequencies are required to inform a safe upper limit for donation frequency.