42 C.F.R. § 412.405
The prospective payment system includes payment for inpatient operating costs of preadmission services if the inpatient operating costs are for—
(a) Preadmission services otherwise payable under Medicare Part B furnished to a beneficiary on the date of the beneficiary's inpatient admission, and during the calendar day immediately preceding the date of the beneficiary's inpatient admission, to the inpatient psychiatric facility that meet the following conditions:
(3) The services are nondiagnostic when furnished on the date of the beneficiary's inpatient admission, the services are nondiagnostic when furnished on the calendar day preceding the date of the beneficiary's inpatient admission and the hospital does not demonstrate that such services are unrelated to the beneficiary's inpatient admission, and are not one of the following:
[75 FR 50415, Aug. 16, 2010]