Deferral due to low hemoglobin and predictors of permanence in the blood donation system of repeat female blood donors

OBJECTIVES: To evaluate the deferral rate due to low hemoglobin (Hb) in repeat female blood donors and identify the factors affecting their permanence in the blood donation system.

MATERIALS AND METHODS: 8,368 repeat female blood donors who donated from January 2012 to December 2018 were included. Bivariate analysis and Kaplan-Meier curves were used to identify the covariates possibly associated with developing low Hb, and Cox proportional hazards modeling was used to adjust for all confounders.

RESULTS: The global deferral rate due to low Hb was 2.4 %. According to baseline Hb, the frequency of low Hb was 0.7-4.1 %, and it was higher in platelet donors (5.8-9.1 %) than in whole blood donors (1.9 %). The main predictors were baseline Hb (compared to the first quartile; hazard ratio [HR] = 0.487 for the second quartile; 0.234 for the third; and 0.095 for the fourth); change in Hb (HR = 2.689 for a >0.49 g/dL change, compared to smaller changes); the type of donation (compared to whole blood donors, HR = 2.317 for platelet donors); and donation interval (compared to >12.5 month intervals; HR = 2.220 for 8.0-12.5 months; HR = 5.658 for 5.4-8.0 months; and HR = 9.452 for <5.4 months).

CONCLUSIONS: In female blood donors at moderate altitude, the probability of developing low Hb increases with a baseline Hb of 13.5-14.0 g/dL, with a change in Hb >0.49 g/dL, in platelet donors, and with donation intervals <12.5 months. These four predictive factors can be used together for early identification of donors at risk of developing low Hb, to institute appropriate measures.