Blood donations are 'gifts' that do not fit easily into a more market-oriented health care system. The new commercial organisational arrangements in New Zealand for the collection, manufacture and distribution of blood and blood products are compared in this paper with the old organisational arrangements. The particular case of screening blood for hepatitis C is examined. A socio-legal framework, which looks at the regulation of social institutions, is used to explore the different ways in which people have tried to maintain the quality of blood and blood products, both in New Zealand and internationally. One conclusion drawn is that blood production and distribution cannot be commercialised without affecting supply and quality.