RESUMEN
Active default tracing is an integral part of tuberculosis (TB) programmatic control. It can be differentiated into the tracing of defaulters (patients not seen at the clinic for > or =2 months) and 'late patients' (late for their scheduled appointments). Tracing is carried out to obtain reliable information about who has truly died, transferred out or stopped treatment, and, if possible, to persuade those who have stopped treatment to resume. This is important because, unlike routine care for non-communicable diseases, TB has the potential for transmission to other members of the community, and therefore presents the issue of the rights of the individual over the rights of the community. For this reason, default or 'late patient' tracing (defined together as default tracing in this article) has been incorporated into standard practice in most TB programmes and, in many industrialised countries, it is also a part of public health legislation. In resource-poor countries with limited access to phones or e-mails, default tracing involves active home visits. In this Unresolved Issues article, we discuss the need for patient consent within both the programmatic and the research context; we describe how this subject arose during operational research training at the Research Institute of Tuberculosis in Japan; we provide comments from individuals who are experienced and skilled at international and national TB control; and finally we offer some conclusions about the way forward. This is not an easy subject, and we welcome open debate on the issue.