(P-PH-8) The Effect of Delayed Return Intervals on Low Hemoglobin Deferrals Among First-Time Whole Blood Donors

Background/Case Studies: In our blood center, 61% of deferrals in 2024 were for low hemoglobin (LHD), which inconveniences donors and lowers blood drive efficiency. While LHD from first-time donors (FTD) are generally uncontrollable, they disincentivize donor return. Minimum interdonation intervals (IDI) were established to allow sufficient hemoglobin (Hb) recovery, yet LHDs remain prevalent. Extending IDI would reduce both collections and LHD, so the benefits of such a change should be balanced against the cost. LHD is uncommon in males but increases across the lifespan. LHD occurs at higher rates in females and with greater variability by age. To evaluate the potential impact of extending IDIs in blood donors, we quantified the association between LHD and IDI at the first return visit for donors with a successful whole blood donation at their first visit. Additionally, to evaluate if baseline Hb might be constrained by nutritional considerations, we modeled the association between LHD at first visit and household income (HI), controlling for demographic factors.

Study

Design/Methods: Donor records were compiled for 2016-2024. Among FTD with a successful WB donation before 2023 (n=5,262,233; 56% female), allowing two years for return, 47% of females and 43% of males returned between 8 weeks and two years. LHD rates for returning donors were plotted by return intervals of weeks since donation (8-12, 13-25, 26-38, 39-51, 52-104), age group, and sex. Median HI by zip code, age, and year was retrieved from the US Census American Communities Survey and matched to FTD by zip code, age and year, grouped into 5 levels (High(ref.), Middle-High, Middle, Low-Middle, Low). Logistic regression, stratified by sex, was used to model the association of LHD and HI controlling for age and race/ethnicity.

Results/Findings: The largest difference in LHD (17% vs. 9.8%) was observed in 16–19-year-old females returning after 8-12 weeks vs. 1-2 years, respectively, narrowing as age increased (Figure A.). Males showed minimal differences across age groups and delay intervals. In multivariable modeling, higher HI was associated with lower odds of LHD in females, Low OR: 2.02 (CI: 1.97, 2.06) and Middle OR: 1.07 (CI: 1.05, 1.09) and similarly in males, Low OR: 2.06 (CI:1.95, 2.19) and Middle OR: 1.20 (CI: 1.14, 1.27).

Conclusions: Not all donors recover quickly following donation and additional research is needed to identify ways to aid donor recovery to maintain a sustainable blood supply. The association of HI with increased odds for LHD among FTD stresses the importance of access to red cell replenishing nutrition as well as the need for guidance to donors interested in ways to hasten recovery.