A surveillance case definition is a set of uniform criteria used to define a disease for public health surveillance. Surveillance case definitions enable public health officials to classify and count cases consistently across reporting jurisdictions. Surveillance case definitions are not intended to be used by healthcare providers for making a clinical diagnosis or determining how to meet an individual patient’s health needs.

While the list of reportable conditions varies by state, the Council of State and Territorial Epidemiologists (CSTE) has recommended that state health departments report cases of selected diseases to CDC’s National Notifiable Diseases Surveillance System (NNDSS).  Every year, case definitions are updated using CSTE’s Position Statements.  They provide uniform criteria of national notifiable infectious and non-infectious conditions for reporting purposes.