Are you a runner? Please join our #Run4HepB team and make your miles matter at the NYC Marathon on November 3! Learn more.


Helpful Terminology

Clinical Trial Status - It is important to know if a study is in the planning, active, or completed stages. When you are looking for clinical trials, you want to pay particular attention to those that are “recruiting.” Here is more information about these terms:

  • Not yet recruiting: The study has not started recruiting participants.
  • Recruiting: The study is currently recruiting participants.
  • Enrolling by invitation: The study is selecting its participants from a population, or group of people, decided on by the researchers in advance. These studies are not open to everyone who meets the eligibility criteria but only to people in that particular population, who are specifically invited to participate.
  • Active, not recruiting: The study is ongoing, and participants are receiving an intervention or being examined, but potential participants are not currently being recruited or enrolled.
  • Suspended: The study has stopped early but may start again.
  • Terminated: The study has stopped early and will not start again. Participants are no longer being examined or treated.
  • Completed: The study has ended normally, and participants are no longer being examined or treated (that is, the last participant's last visit has occurred).
  • Withdrawn: The study stopped early, before enrolling its first participant.
  • Unknown: The study is considered closed since the trial status has not been verified for at least 2 years.

Study Type -When looking for a clinical study, it is important to know what type of study you are looking for, and what type each listed study is:

  • Interventional Study: A type of clinical study in which participants are assigned to groups that receive one or more intervention/treatment (or no intervention) so that researchers can evaluate the effects of the interventions on biomedical or health-related outcomes. The assignments are determined by the study's protocol. Participants may receive diagnostic, therapeutic, or other types of interventions.
  • Observational Study: A type of clinical study in which participants are identified as belonging to study groups and are assessed for biomedical or health outcomes. Participants may receive diagnostic, therapeutic, or other types of interventions, but the investigator does not assign participants to a specific interventions/treatment.
  • Expanded Access: This is a way for patients with serious diseases or conditions who cannot participate in a clinical trial to gain access to a medical product that has not been approved by the Food and Drug Administration. It is also called compassionate use.
  • Cohort Study: A type of medical research used to investigate the causes of disease, establishing links between risk factors and health outcomes. They are usually forward-looking - that is, they are "prospective" studies, or planned in advance and carried out over a future period of time.

Eligibility criteria - These are requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Some studies will list both “inclusion” criteria, which are required for a person to participate in the study - and “exclusion” criteria, which prevent a person from participating. Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by gender.

For a full list of terms, you can visit the glossary.


*Terminology was referenced from