What is the subject?

In clinical trials, a subject is an individual who takes part in the study, either as a patient, healthy volunteer, or participant, depending on the trial type. The subject undergoes study procedures, assessments, or treatments according to the trial protocol. Essentially, the subject is the person whose data and responses are being collected to evaluate the safety, efficacy, or outcomes of the intervention being studied.

In clinical trials, a subject is involved throughout the study, from screening and enrollment to study visits and follow-ups. Subjects are used to collect data on the effects, safety, and efficacy of the investigational product or intervention. Their participation is essential for evaluating trial outcomes, monitoring adverse events, and ensuring that study results are accurate and reliable. Subjects also provide informed consent, allowing researchers to conduct procedures, record observations, and maintain study records in compliance with the protocol. Essentially, every stage of the trial, recruitment, enrollment, treatment, assessments, and follow-up relies on the participation of subjects.

Effective recruitment also supports planning for site activities, visit schedules, and resource allocation. By enrolling a balanced and representative participant population, recruitment helps the trial progress smoothly and ensures reliable results that meet both scientific and regulatory objectives.

In clinical trials, subject management is implemented by systematically tracking individuals throughout their participation in the study. Once identified, each subject is assigned a unique study ID and linked to defined visits, procedures, and assessments. Their data, including observations and outcomes, is recorded against these activities to ensure consistency with the study protocol. This structured approach helps sites monitor subject progress, manage study tasks efficiently, and maintain accurate records from screening through study completion.

In real-world use, a subject is seen as an active participant with a unique study ID in the trial system. Site staff schedule the subject’s visits, perform required assessments, and record observations at each visit. Any changes, such as missed visits or reported events, are documented against the subject record. This allows the study team to follow the subject’s journey clearly from enrollment through follow-up while ensuring all activities align with the study protocol.

Patient

Participant

Informed Consent

Eligibility Criteria

Enrollment

ePRO Software for Clinical Trials
A Guide to ePRO: Electronic Patient-Reported Outcomes 

ePRO / eCOA