Medical surveillance and screening in the workplace: complementary preventive strategies.

The terms medical surveillance and medical screening have sometimes been used interchangeably in the occupational medicine literature. Recently attempts have been made to redefine these as mutually exclusive, by nesting surveillance under screening or vice versa, by subsuming both under medical monitoring or periodic examinations, or by eliminating use of the term medical surveillance altogether. In this paper I argue that medical surveillance and medical screening represent discrete concepts and approaches and should be viewed as distinct and complementary secondary preventive components of an occupational health program. Medical surveillance refers to the periodic examination of putatively exposed workers, and is therefore a longitudinal approach. Medical screening refers to the cross-sectional testing or evaluation of a group of workers. Biological monitoring, whether defined narrowly or broadly, focuses on exposure to particular toxicants and should serve as a component of medical surveillance (or of medical screening), not as an independent complement to environmental monitoring. Medical surveillance must function in the context of a comprehensive occupational health program that includes industrial hygiene and education and does not in itself suffice as a comprehensive occupational health program. It is useful to clarify these terms because some of the ethical issues as well as medical controversies over their utility arise from a misunderstanding of what constitutes medical surveillance and how it should be applied.