If you don't understand any portion of the consent, ask your doctor to explain it to you. Before you can participate in a clinical trial, you must sign the informed consent form. This shows that you have been given the required information and that you understand it. Remember, that even after you have signed the consent, you may quit the study at any time. The protocol for the trial determines who can participate.
Different trials look at different groups of patients.
These groups may be based on such factors as age, type of disease, medical history and current medical condition. Some trials seek volunteers with particular illnesses or conditions, while other trials need healthy volunteers. Healthy volunteers are most often used in Phase I trials, vaccine studies and trials on preventive care. The factors that allow you to participate in a trial are called inclusion criteria. The factors that prevent you from being a participant are called exclusion criteria.