Tests may provide valuable information for identification or prediction functions. Examples include disease diagnosis and staging, therapeutic outcome prediction, outbreak detection, infection control policy compliance monitoring, and other quality assurance monitoring. However, the importance of information from specific tests depends on their validity and utility Thus, hospital epidemiologists who assess new or existing tests themselves should bear in mind “…a clear need for greater attention to accepted methodological standards on the part of researchers, reviewers and editors.”’ Poorly validated tests can produce harmful, misleading results.