Science in action? A critical view of UK blood donation deferral policy and men who have sex with men.

The rules that govern blood donation vary globally. Some potential blood donors are ineligible for immediate blood donation, and as such are deferred until such time that they become eligible. This practice, the blood donation deferral period, is intended to reduce the risk of blood-borne infections being transfused into a blood product-recipient. As blood screening technologies improve, the risk of an infected blood product remaining undetected decreases-and so too have the deferral periods for certain donors. Much has been made of the importance of an evidence-based, scientific approach to protecting blood product-recipients. However, these deferrals are controversial. What exactly determines the blood donation deferral period? This article argues that blood donation deferral periods are not merely the result of enacting empirical data. Instead, the deferral periods represent a negotiation between scientific evidence, experts, politically expedient narratives, institutionalised risk aversion, as well as more mundane concerns such as operational feasibility. As a case study, I examine how the UK Advisory Committee on the Safety of Blood, Tissues and Organs changed the 12-month deferral period for blood donation from men who have sex with men to a 3-month deferral period.