Expected outcomes of stratified post-donation testing in whole blood donation in England: A discrete event simulation modeling study.

Background: In England, blood donors with low hemoglobin concentration are deferred following on-session testing to prevent donations below regulatory thresholds, thereby protecting donors' health and blood supply quality. However, deferrals are costly, time-consuming and may discourage donors. Post-donation testing (PDT), where hemoglobin levels are measured after donation, offer potential alternatives as used in some European countries.

Study design and methods: We compared four PDT strategies to the current approach: (A) no on-session testing, (B) on-session testing if low hemoglobin at previous visit, (C) on-session testing if low/medium hemoglobin at previous visit, all with delayed reinvitation if low hemoglobin at previous donation, and (D) on-session testing if low/medium hemoglobin at previous visit without delayed reinvitations. We employed discrete event simulation modeling, informed by data collected from 16,941 donors returning under the current strategy in England, to simulate and compare total donations, under-threshold donations, and deferrals for each strategy over 18 months.

Results: Strategy A eliminated deferrals but led to increased under-threshold donations compared to the current strategy in men (6.5% vs. 2.3%) and women (11.8% vs. 4.5%). Strategies B-D reduced deferrals rates for men (1.0%-3.7% vs. 5.5%) and women (2.2%-6.3% vs. 8.9%) but showed slightly higher under-threshold donations in men (3.0%-5.1% vs. 2.3%) and women (5.3%-8.8% vs. 4.5%). Strategies with more on-session testing had lower under-threshold donations.

Discussion: PDT strategies incorporating on-session testing for low/medium hemoglobin at previous visits could reduce deferrals while maintaining a low proportion of under-threshold donations, thereby balancing donor safety with operational efficiency.