pre-specified characteristics or conditions that disqualify an individual from participating in a research study or clinical trial. These criteria are established before recruitment begins and are used to protect participant safety, ensure data quality, and maintain the integrity of the study design.
Example
A cardiovascular drug trial lists the following exclusion criteria: participants younger than 18 years old, pregnant or breastfeeding individuals, people with severe kidney impairment, and those unable to attend required follow-up visits. Anyone meeting one or more of these conditions cannot enroll in the study.