What is the purpose of a case definition in surveillance?

• A. A uniform set of criteria used to classify whether a person has the disease for surveillance
• B. To list all suspected cases in a population
• C. To determine laboratory testing protocols
• D. To allocate resources for vaccination

Answer: (A)

Case definitions in surveillance provide a uniform, standardized set of criteria to decide whether a person is considered a case for reporting. This standardization lets data be comparable over time and across different places, enabling accurate trend detection and timely public health responses. They often combine specific clinical signs with laboratory evidence and may include levels of certainty (suspected, probable, confirmed). This focus on consistent classification is what makes surveillance data meaningful. It isn’t meant to list every suspected case, dictate laboratory testing protocols, or determine vaccination resource allocation, which are separate activities.