Understanding Trial Eligibility Criteria

Why eligibility criteria exist

Eligibility criteria define who can and cannot join a trial. They help researchers answer a specific question while protecting participants from avoidable risk.

Criteria can feel frustrating when they rule someone out, but they are usually there for safety, scientific accuracy, or both.

Inclusion criteria

Inclusion criteria describe what must be true for someone to join. These might include age, diagnosis, disease stage, test results, previous treatments, symptoms, or ability to attend visits.

For example, a cancer trial may require a specific biomarker. An autoimmune trial may require symptoms to be active despite standard treatment.

Exclusion criteria

Exclusion criteria describe situations that would make participation unsuitable. These might include certain medications, recent surgery, other health conditions, pregnancy, abnormal lab results, or previous exposure to a similar treatment.

Being excluded is not a judgement on the patient. It usually means the trial is not designed for that exact situation.

Why matching can be uncertain

Trial records do not always contain every detail in patient-friendly language. Some criteria require medical interpretation or recent test results.

That is why a TrialConnect match should be treated as an informed lead. Screening by the research team is the step that confirms whether the trial is actually open to you.

How to prepare for screening

• Know your exact diagnosis and subtype if you have one.
• Ask for key biomarker or genetic test results if relevant.
• Keep a rough timeline of previous treatments and dates.
• List current medicines and important other conditions.
• Write down any criteria you do not understand before speaking to the trial team.