42 CFR § 409.12 - Nursing and related services, medical social services; use of hospital or CAH facilities.
(a) Except as provided in paragraph (b) of this section, Medicare pays for nursing and related services, use of hospital or CAH facilities, and medical social services as inpatient hospital or inpatient CAH services only if those services are ordinarily furnished by the hospital or CAH, respectively, for the care and treatment of inpatients.
(b) Exception. Medicare does not pay for the services of a private duty nurse or attendant. An individual is not considered to be a private duty nurse or attendant if he or she is a hospital or CAH employee at the time the services are furnished.