Medical surveillance - sounds ominous, but it's a critical safety tool used to detect early signs of work-related illness. In general industry, it's used as a backup to an industrial hygiene assessment. This systematic collection and analysis of data can lead to early detection and sometimes even predict an unidentified exposure.
In addition to early detection, sometimes additional disease and injury risk factors come to light during surveillance. As an added benefit, an intervention may detect a non-work-related disease and promote opportunities for increasing workplace health.