How anonymous is 'anonymous'? Some suggestions towards a coherent universal coding system for genetic samples.

So-called 'anonymous' tissue samples are widely used in research. Because they lack externally identifying information, they are viewed as useful in reconciling conflicts between the control, privacy and confidentiality interests of those from whom the samples originated and the public (or commercial) interest in carrying out research, as reflected in 'consent or anonymise' policies. High level guidance documents suggest that withdrawal of consent and samples and the provision of feedback are impossible in the case of anonymous samples. In view of recent developments in science and consumer-driven genomics the authors argue that such statements are misleading and only muddle complex ethical questions about possible entitlements to control over samples. The authors therefore propose that terms such as 'anonymised', 'anonymous' or 'non-identifiable' be removed entirely from documents describing research samples, especially from those aimed at the public. This is necessary as a matter of conceptual clarity and because failure to do so may jeopardise public trust in the governance of large scale databases. As there is wide variation in the taxonomy for tissue samples and no uniform national or international standards, the authors propose that a numeral-based universal coding system be implemented that focuses on specifying incremental levels of identifiability, rather than use terms that imply that the reidentification of research samples and associated actions are categorically impossible.