CMS Pub. 100-01, ch. 3, § 10.4.1

A benefit period begins with the first day (not included in a previous benefit period) on

which a patient is furnished inpatient hospital or extended care services by a qualified

provider in a month for which the patient is entitled to hospital insurance benefits.

A provider qualified to start a benefit period is a hospital (including a psychiatric

hospital) or SNF that meets all the requirements of the definition of such an institution.

A hospital which meets all requirements in Chapter 5, §20 of this manual is also a

qualified hospital for purposes of beginning a benefit period when it furnishes the patient

covered inpatient emergency services. Thus, generally, the benefit period begins when

covered inpatient services are initially furnished to an entitled individual. However, the

noncovered services furnished by a nonparticipating provider can begin a spell of illness

only if the provider is a qualified provider. A qualified provider is a hospital (including a

psychiatric hospital) or a SNF which meets all requirements in the definition of such an

institution even though it may not be participating. A qualified hospital in Canada or

Mexico is also a qualified provider for purposes of beginning a benefit period when it

furnishes covered inpatient hospital services. If a person is in a nonqualified institution

and is subsequently transferred to a qualified hospital (general or psychiatric), his/her

benefit period begins on admission to the qualified hospital.

Admission to a qualified SNF or to the SNF level of care in a swing-bed hospital begins a

benefit period even though payment for the services cannot be made because the prior

hospitalization or thirty-day transfer requirement has not been met. It is also worth

noting that the SNF benefit’s “thirty-day” transfer requirement has a medical

appropriateness exception (described in Pub. 100-02, Medicare Benefit Policy Manual,

chapter 8, section 20.2.2), under which the allowable interval between a beneficiary’s

discharge from a qualifying prior hospitalization and the initiation of SNF care can

exceed the normal 30-day timeframe; moreover, in a situation where the allowable

interval under this exception is 60 days or longer, the subsequent commencement of

extended care services in the SNF would serve to trigger the start of a new benefit period.

Inpatient care in a Religious Non-Medical Health Care Institution (whether as hospital or

extended care services) can begin or prolong a benefit period.