Participant recruitment and participation

Phase 0 and phase 1 drug trials seek healthy volunteers. Most other clinical trials seek patients who have a specific disease or medical condition. The diversity observed in society, by consensus, should be reflected in clinical trials through the appropriate inclusion of ethnic minority populations.^[72] Patient recruitment or participant recruitment (as some participants in clinical trials are considered 'healthy' and not patients) plays a significant role in the activities and responsibilities of sites conducting clinical trials.^[73]

Locating trials

Depending on the kind of participants required, sponsors of clinical trials, or contract research organizations working on their behalf, try to find sites with qualified personnel as well as access to patients who could participate in the trial. Working with those sites, they may use various recruitment strategies, including patient databases, newspaper and radio advertisements, flyers, posters in places the patients might go (such as doctor's offices), and personal recruitment of patients by investigators.
Volunteers with specific conditions or diseases have additional online resources to help them locate clinical trials. For example, the Fox Trial Finder connects Parkinson's disease trials around the world to volunteers who have a specific set of criteria such as location, age, and symptoms.^[74] Other disease-specific services exist for volunteers to find trials related to their condition.^[75] Volunteers may search directly on ClinicalTrials.gov to locate trials using a registry run by the U.S. National Institutes of Health and National Library of Medicine.
However, many clinical trials will not accept participants who contact them directly to volunteer, as it is believed this may bias the characteristics of the population being studied. Such trials typically recruit via networks of medical professionals who ask their individual patients to consider enrollment.^{[citation needed]}

Steps for volunteers

Before participating in a clinical trial, interested volunteers should speak with their doctors, family members, and others who have participated in trials in the past. After locating a trial, volunteers will often have the opportunity to speak or e-mail the clinical trial coordinator for more information and to answer any questions. After receiving consent from their doctors, volunteers then arrange an appointment for a screening visit with the trial coordinator.^[76]
All volunteers being considered for a trial are required to undertake a medical screening. Requirements differ according to the trial needs, but typically volunteers would be screened in a medical laboratory for:^[76]

• Measurement of the electrical activity of the heart (ECG)
• Measurement of blood pressure, heart rate and body temperature
• Blood sampling
• Urine sampling
• Weight and height measurement
• Drug abuse testing
• Pregnancy testing

Volunteers have the right to know and understand the details of what will happen during a clinical trial, a process called informed consent.^[76]

Research

In 2012, Z. Janet Yang, Katherine A. McComas, Geri K. Gay, John P. Leonard, Andrew J. Dannenberg, and Hildy Dillon conducted research on the attitudes towards clinical trial treatment and the decision making of signing up for such trials by cancer patients and the general population. They used the risk information seeking and processing (RISP) model to analyze the social implications that affect attitudes and decision making pertaining to clinical trials. People who hold a higher stake or interest in clinical trial treatment showed a greater likelihood of seeking information about clinical trials. Those with networks that stress the importance of learning about clinical trials are also more likely to seek and process information more deeply. People with more knowledge about clinical trials tend to have to a greater likelihood of signing up. In the study, cancer patients reported more optimistic attitudes towards clinical trials than the general population. Having a more optimistic outlook on clinical trials also leads to greater likelihood of enrolling.^[77]