Background: On-site deferral for low hemoglobin (Hb) is common in most countries and deferral rates commonly vary between 1% and 20%. Blood banks continuously strive to reduce deferral rates as these imply an immediate loss of products, a waste of materials, a waste of staff and donor time, and potential loss of donors. Despite many efforts, the main cause of donor deferral-the variability in hemoglobin measurement outcomes-remains largely unaddressed.Study Design and Methods: Repeated hemoglobin measurements obtained at donor intake were used to estimate the variability in measurement outcomes (measurement variability). This information is incorporated in a new algorithm for donor deferral where the mean hemoglobin level of a donor is used to determine both donor eligibility and the deviance of individual measurement outcomes. The algorithm was tested on a cohort of new Dutch donors that started between 2012 and 2022 to evaluate its impact on the donor deferral rate. Results: Historical data from 439,376 new donors with a deferral rate of 5.3% were analyzed by applying the new donor deferral algorithm. It was found that 92% of all deferrals were unnecessary as Hb levels were within the range of expected measurement variability. Contrarily, it appeared that 460 donors (0.10%) made 704 donations (0.06%) whilst not complying with donor eligibility criteria.Discussion: Not accounting for measurement variability can be shown to not only result in unnecessary on-site deferrals but also results in donations by donors that can be shown not to comply with the legally required minimum Hb levels.donor deferral, donor risk management, hemoglobin measurement variability
| INTRODUCTIONDonor screening and deferral to guarantee the safety of blood donors have been a topic of research and debate ever since the first reporting of negative side effects of blood donation. 1,2 In the Netherlands, as in most countries, pre-donation testing is applied before each donation, and donors with Hb levels below a set Hb threshold are temporarily deferred. European law prescribes a minimum weight for a donor of 50 kg, and minimum