Other treatment trials test procedures such as surgery, technology or devices, or educational interventions. Prevention trials test ways to prevent specific health conditions. Drugs, vitamins, education, life style changes, or other interventions may be tested in prevention trials. Screening trials test ways to detect and diagnose health conditions and diseases. Clinical trials are designed to test the effect of these interventions on patient outcomes.
Most clinical trials move through steps, called phases.
Each phase is designed to ask and answer specific questions in a way that provides reliable information to researchers while protecting the participants. The standard of using phases of testing grew out of the drug approval process. It is now used for many different kinds of clinical trials. A new intervention must successfully pass through one testing phase before moving on to the next. But testing can be stopped at any time in any phase in order to ensure the safety of participants.