The Establissement français des Greffes (EfG) is a state agency dealing with Public Health issues related to organ, tissue and cell transplantation in France. EfG maintains a national information system (EfG-IS) for the evaluation of organ transplantation activities. The EfG-IS is moving toward a new n-tier architecture comprising a terminological server. Because this terminological server is shared by various kind of transplant teams and dialysis centers to record patients data at different time point, contextualisation of terms appeared as a functional requirement. We report in this paper various contexts for medical terms and how they have been taken into account.