Prediction models for hemoglobin deferral in whole blood donors

Each year, a relevant proportion of the invited blood donors is eventually deferred from donation because of low hemoglobin (Hb) levels. Deferrals are meant to protect donors from developing iron deficiency anemia after a blood donation, however, they may increase the risk of donor lapse, even though the donor may actually meet the Hb criterion at the time of the next donation invitation. Early estimation of the risk of Hb deferral on the next visit to the blood collection center could be helpful in the management of the blood donation program.

As a PhD student, Mireille Baart developed prediction models for Hb deferral risk in whole blood donors. The prediction models were developed in Dutch whole blood donors. Predictive factors in the models are Hb level measured at the previous visit, age, seasonality, difference in Hb levels between the previous two visits, time since the previous visit, deferral at the previous visit, and the total number of whole blood donations in the past two years. The models were externally validated in a cohort of Irish donors. After updating the models to the Irish situation the performance of the models was satisfactory. Subsequently, the added value of zinc protoporphyrin (ZPP) levels to the prediction models was investigated. Results showed that addition of ZPP improved the model performance.

Results from studies on the prediction models show that with a limited number of easy-to-measure characteristics the risk of Hb deferral in whole blood donors can be reliably predicted. The model predictions could be helpful in the management of the donation program by applying them in the invitation process of blood donors. Donors with a low predicted risk of Hb deferral can be invited for a donation with preference, whereas for donors with a high risk of Hb deferral interventions such as postponement of the invitation for donation or a dietary advice are warranted.

As a postdoc, Mireille Baart is working on an impact study of the prediction models. In this study, the effectiveness of using the models for the selective invitation of donors with a low risk of Hb deferral will be evaluated in terms of the number of Hb deferrals, donor lapse and costs. Results of this study will show whether implementation of the prediction models in practice would be valuable.

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