Recent sociological analyses of the intersections of race and science recognise race's quality as an enacted object. Through this analytic lens, race is always materialising in the practices and processes that enrol it and therefore enjoys a kind of multiplicity. The context of blood stem cell transplantation, a scientific domain marked by a more and less explicitly racialised logic, offers an opportunity to see the conceptual assertion of race's multiplicity play out. Indeed, an exploration of the UK's stem cell inventory reveals-through analysis of interviews, policy and parliamentary meetings-how race materialises in the various practices that comprise this increasingly popular cancer treatment option. Looking at practices of recruitment, inventory management and tissue selection in particular provides an interesting window to look upon race and the many signifiers that implicate it. These cases reveal moments of race's stablisation and silencing; its oscillation between the status of vital information to the life of a public stem cell inventory, and of secondary data that provides little useful information to clinicians selecting tissue. Adopting an analytic lens that attends to race's multiple enactments allows us to begin asking why enactments take the shape they do, and why the particular practices that mobilise them come to be.