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Sometimes we have to postpone a blood donation because the donor has for example low haemoglobin values or just got a tattoo. In this project, we looked at the effects of deferral on donor return as well as how to prevent donors from lapsing after deferral. On-site deferral can be disappointing and costly for both donors and blood banks. The first study in this project showed that especially new and reactivated donors are at risk of lapsing from the donor pool when they are deferred on-site, while also being at higher risk of being deferred on-site (Spekman, Van Tilburg & Merz, 2019). In order to prevent donors from lapsing after they are temporarily deferred on-site, we set up a large field RCT to study effects of different methods to motivate donors to return (Spekman, Van Tilburg, & Merz, 2022). Findings showed that offering an alternative good deed (such as writing a card for a patient or filling out a survey to help Sanquin get more insights into their donors) did not significantly increase the return rate of deferred donors, while providing deferred donors with additional information about the importance of deferral to protect donor and patient health did lead to an increase in return (compared to the control group who received no intervention). This finding aligns with findings from similar studies that have appeared around the same time in suggesting that donor retention may benefit from paying more attention to deferred donors, especially when they are deferred on-site.


Marloes Spekman is a postdoctoral researcher at the Donor Medicine Research department of Sanquin. She has a background in Communication Science and Media Psychology. Her research focuses on the psychological and social aspects of blood and plasma donation.

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Providing Extra Information Increases Blood Donor Return After Deferral While Offering an Alternative Good Deed Does Not: Results From a Field Randomized Controlled Trial.

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Do deferred donors continue their donations? A large-scale register study on whole blood donor return in the Netherlands. 

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Whole blood donor behavior and availability after deferral: Consequences of a new ferritin monitoring policy.  

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