В ММ лексема остутствует. Давайте подумаем, как это наиболее адекватно перевести.

Сертифицированный? Дипломированный? Уполномоченный?

Только не доверенный, т.к. "доверенный доктор" -- это trusted doctor, знаю наверняка.

Двухсмыслённость, однако.

a few random thoughts:

- с подтвержденной (профессиональной) квалификацией
- квалифицированный (хотя здесь возможна двусмысленность)
в российском контексте, ближе всего, по-моему, "дипломированный"

Usage Note: The use of the participle credentialed to refer to certified teachers and other professionals is well established (She became credentialed through a graduate program at a local college), but its more general use to mean "possessing professional or expert credentials" is still widely considered jargon. The sentence The board heard testimony from a number of credentialed witnesses was unacceptable to 85 percent of the Usage Panel.

Мне кажется, лучше всего "сертифицированный/дипломированный" (и в голове у меня оно тяготеет к licensed в licensed practical nurse, напр)

See: http://encyclopedia.thefreedictionary.com/credential

A credential is an attestation of qualification, competence, or authority issued to an individual by a third party with a relevant de jure or de facto authority or assumed competence to do so. Examples of credentials include academic diplomas, academic degrees, and certifications, security clearances, identification documents, badges, passwords and user names, keys, powers of attorney, and so on.
A few examples of credentials and their associated documentation are given below; this list is far from exhaustive.

Types and documentation of credentials
Medicine
In medicine, the process of credentialing is a detailed review of all permissions granted a medical doctor at every institution at which they've worked in the past, to determine a risk profile for trusting them at a new institution. Most medical practitioners also must have credentials in the form of licenses issued by the government of the jurisdictions in which they practice, which they obtain after suitable education, training, and/or practical experience. Most medical credentials are granted for life, but may be withdrawn in the event of fraud or malpractice by their holders.

Trade credentials
Some trades and professions in some jurisdictions require special credentials of anyone practicing the trade or profession. These credentials may or may not be associated with specific competencies or skills. In some cases, they exist mainly to control the number of people who are allowed to exercise a trade or profession, in order to control salaries and wages.
Persons acting as merchants, freelancers, etc., may require special credentials in some jurisdictions as well. Here again, the purpose is mainly to control the number of people working in this way, and sometimes also to track them for tax-reporting or other purposes.

Academic credentials
The academic world makes very extensive use of credentials, such as diplomas, certificates, and degrees, in order to attest to the completion of specific training or education programs by students, and to attest to their successful completion of tests and exams.
Documentation of academic credentials usually consists of a printed, formal document designed to last a lifetime without deterioration. The issuing institution often maintains a record of the credential as well. Academic credentials are normally valid for the lifetime of the person to whom they are issued.