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Who can take part

Every study sets out who can and can't take part. Those rules are called eligibility criteria.

Last reviewed 14 September 2026

Two lists

Inclusion criteria

What participants need to have, such as an age range, a diagnosis, or a stage of a condition.

Exclusion criteria

What rules someone out, such as another condition, a medicine they take, or pregnancy, often for safety.

Why they exist

Criteria keep participants safe and make sure the study can answer its question. They're about the research, not a judgement of anyone.

Meeting the listed criteria doesn't guarantee a place. The study team screens each person, and only they decide who takes part.

This is general information, not medical advice. Talk to your doctor about whether a study could be right for you, and to the study team about the details of a specific study.

Sources

Written from public information published by ClinicalTrials.gov (U.S. National Library of Medicine) and the U.S. National Institutes of Health.