In order to organize a nationwide program for the evaluation of professional practices in the area of blood transfusion, the French National Blood Transfusion Institute and the Nice-Sophia Antipolis University designed and implemented a web based service aimed at following-up and guiding the physicians involved in such an assessment program. The core component is a structured electronic portfolio (ePortfolio), the implementation of which was based on an object-oriented environment combined with a content management system. The modelling of the global evaluation system makes it possible to describe this type of portfolio according to six axes: an axis "objectives" (competencies accreditation); an axis "target" (heath care professionals); an axis "content" (numerical documents); an axis "structure" (matrix of answer defined in space and time); an axis "source" (single source peer-reviewed); an axis "level of evidence" (validation of the proof after its deposit by an identified and authenticated peer user, whole tracking of the exchanges and interactions between users and device).