[Health surveillance: scope, tools, efficacy, prospects].

According to experts of the European Commission, NIOSH and OSHA, health surveillance's goal is the both health protection and occupational diseases prevention (including injury and uneasiness). This goal is pursued by assigning workers according to his or her working capacity without any health prejudice. Currently available instruments to protect workers' health include: (i) medical surveillance before employment, (ii) medical surveillance before placement in a job involving exposure to toxics, (iii) medical surveillance at periodic intervals during employment, (iv) medical surveillance at termination of employment. Studies carried out on the efficacy of medical surveillance show the capacity both of identifying health problem and of being perceived as a benefit for workers. An appropriate application of medical surveillance should take into account points as efficacy, guidelines, costs and benefits, and effectiveness. This entails the need to carry out research aiming (i) to make the importance of currently used preventive instruments explicit and (ii) to study new approaches to be applied in occupational health care.