The possibility of making scientifically objective statements about health risks is part of a new complex of ideas pervading our Western social institutions. The concept of prevention includes an assessment of risk and dangers which lay persons have difficulties in comprehending. Advances in medical technology have made it possible to detect a growing number of anomalies in the human body and thereby to define more and more people as being at risk of various diseases. Even if it seems desirable for society to be able to detect the risks menacing its members, it calls for delicate management of the test procedures and of the preventive intervention. This article presents some perspectives on preventive work in connection with a directed health survey. The primary aim of the survey in question was to diagnose particular risk factors, for instance a high level of blood cholesterol, and inform the patient about how to prevent or reduce the risk of cardiovascular disease. The preventive measures are commonly undertaken by a nurse; her encounters with the patients—to obtain test samples, communicate the results and provide information about health risks—raise complex issues. These and other dilemmas in preventive work are discussed and anal