Trial reference number

The National Clinical Trial (NCT) number is an identification number that the website assigns to a trial when it is registered. The NCT number is in the format “NCTXXXXXXXX”. The trial is not registered until an NCT number is assigned.

Trial name

The official title of a clinical trial. Sometimes a trial also has a short title written in language that is easier for the public to understand.

Trial purpose

The main reason for the clinical trial. The primary purpose types include treatment, prevention, diagnostic, quality of life (supportive care), screening, and others.


A clinical trial’s requirements (criteria) for people who want to join. Eligibility criteria consists of:

  • Inclusion criteria, which are factors (such as age, race, sex, or condition) that allow a person to join a trial
  • Exclusion criteria, which are factors or conditions that are not permitted in a trial

About the trial/trial design

The research methods and strategies used in the clinical trial.

Trial phases

The phase of the clinical trial, which is a number 1 through 4. The phase is based on the trial’s goals, the number of participants, and other characteristics.

Learn more about the 4 clinical trial phases


Trial dates

The start date is the actual date on which the first participant was enrolled in a clinical trial. The “estimated” start date is the date that the researchers think the trial will start.

Still have questions?

Our FAQ section has answers to commonly asked questions and a glossary of words to know.

Frequently asked questions