Who can join · reviewed 2026-08-17
Eligibility criteria, explained in plain English
What inclusion and exclusion criteria are, why trials use them, and how to read them on ClinicalTrials.gov. Not a determination of whether you qualify.
Inclusion vs exclusion
Inclusion criteria are the boxes a protocol wants checked (diagnosis, age, prior therapy, organ function). Exclusion criteria are the boxes that usually stop enrollment (certain other diseases, medicines, pregnancy, recent procedures).
PlainTrials splits the public eligibility block into “who it is for” and “who the registry excludes.” That split is a reading aid. It is not a medical clearance.
Why protocols are strict
Trials answer a specific scientific question. Mixing very different patients can hide a signal or raise risk. Strict criteria protect participants and keep the question interpretable. They also mean many people who want to join will not match a given NCT number. That is not a judgment of your worth.
Hidden details live in the full protocol
The public registry is a summary. Lab cutoffs, washout periods, and imaging windows may be more detailed in the protocol the site uses. If a public line is unclear, ask the coordinator to explain it — do not guess from a rewrite.
Healthy volunteers
Some phase 1 records enroll people without the disease to study safety and blood levels. Those studies are labeled on the registry. Do not assume a disease-condition hub includes healthy-volunteer studies unless the card says so.