Clinical case definition

In epidemiology, a clinical case definition, a clinical definition, or simply a case definition lists the clinical criteria by which public health professionals determine whether a person's illness is included as a case in an outbreak investigation—that is, whether a person is considered directly affected by an outbreak. Absent an outbreak, case definitions are used in the surveillance of public health in order to categorize those conditions present in a population (e.g., incidence and prevalence).