"voluntary subject" is correct and usable in written English.
You can use this phrase when referring to an individual who has agreed to participate in a study or practice, usually through informed consent. For example: The results from the study were based on analysis of a sample of 30 voluntary subjects.
Public, private or voluntary, subjected to the same disinfecting transparency of FoI".
She performs complex biological tests on numerous blood and sputum samples supplied by voluntary subjects.
Twenty-one patients participated in the study as voluntary subjects, all of whom completed two sessions of Buddhist counseling interventions.
In ten typical air-conditioned office buildings, 1174 voluntary subjects have completed 3742 questionnaires, while their thermal environments were simultaneously being measured.
Twenty-five voluntary subjects participated also in a reliability assessment 1 week later, conducted by a different interviewer.
To conduct our research we recruited about 9000 voluntary subjects in 8 selected villages: Talana, Urzulei, Baunei, Triei, Seui, Seulo, Ussassai and Loceri (figure 1).
A modified questionnaire was used to collect information on individual chemical-related sensitivity from voluntary subjects (Table 1).
Phase 2 phenotyping studies are voluntary; subjects can choose to take part in some studies and not in others.
Participants were not randomly chosen, and participation was voluntary (subjects accepted to take part in the assessment on reaching the webpage for the online questionnaire).
This study included 100 subjects with acute myocardial infarctus (AMI), acute pulmonary embolism, deep vein thrombosis, ischemic cerebrovascular disease (ICD), acute mesentery embolism, and peripheric artery embolism (PAE), and 110 healthy voluntary subjects were included in the control group.
