22 CFR §42.66

1. (a)Medical examination required of all applicants. Before the issuance of an immigrant visa, the consular officer shall require every alien, regardless of age, to undergo a medical examination in order to determine eligibility to receive a visa.
2. (b)Examination by physician from approved panel. The required examination shall be conducted in accordance with requirements and procedures established by the United States Public Health Service and by a physician selected by the alien from a panel of physicians approved by the consular officer.
3. (c)Facilities required for panel physician. A consular officer shall not include the name of a physician on the panel of physicians referred to in paragraph (b) of this section unless the physician has facilities to perform required serological and X-ray tests or is in a position to refer applicants to a qualified laboratory for such tests.