California Code, Business and Professions Code - BPC § 680

(a) Except as otherwise provided in this section, a health care practitioner shall disclose, while working, his or her name and practitioner's license status, as granted by this state, on a name tag in at least 18-point type. A health care practitioner in a practice or an office, whose license is prominently displayed, may opt to not wear a name tag. If a health care practitioner or a licensed clinical social worker is working in a psychiatric setting or in a setting that is not licensed by the state, the employing entity or agency shall have the discretion to make an exception from the name tag requirement for individual safety or therapeutic concerns. In the interest of public safety and consumer awareness, it shall be unlawful for any person to use the title “nurse” in reference to himself or herself and in any capacity, except for an individual who is a registered nurse or a licensed vocational nurse, or as otherwise provided in Section 2800. Nothing in this section shall prohibit a certified nurse assistant from using his or her title.

(b) Facilities licensed by the State Department of Social Services, the State Department of Public Health, or the State Department of Health Care Services shall develop and implement policies to ensure that health care practitioners providing care in those facilities are in compliance with subdivision (a). The State Department of Social Services, the State Department of Public Health, and the State Department of Health Care Services shall verify through periodic inspections that the policies required pursuant to subdivision (a) have been developed and implemented by the respective licensed facilities.

(c) For purposes of this article, “health care practitioner” means any person who engages in acts that are the subject of licensure or regulation under this division or under any initiative act referred to in this division.