42 CFR § 409.61 - General limitations on amount of benefits.
(a) Inpatient hospital or inpatient CAH services -
(i) For the first 60 days (referred to in this subpart as full benefit days), Medicare pays the hospital or CAH for all covered services furnished the beneficiary, except for a deductible which is the beneficiary's responsibility. (Section 409.82 specifies the requirements for the inpatient hospital deductible.)
(ii) For the next 30 days (referred to in this subpart as coinsurance days), Medicare pays for all covered services except for a daily coinsurance amount, which is the beneficiary's responsibility. (Section 409.83 specifies the inpatient hospital coinsurance amounts.)
(2) Lifetime reserve days. Each beneficiary has a non-renewable lifetime reserve of 60 days of inpatient hospital or inpatient CAH services that he may draw upon whenever he is hospitalized for more than 90 days in a benefit period. Upon exhaustion of the regular benefit days, the reserve days will be used unless the beneficiary elects not to use them, as provided in § 409.65. For lifetime reserve days, Medicare pays for all covered services except for a daily coinsurance amount that is the beneficiary's responsibility. (See § 409.83.)
(i) The 60 full benefit days;
(ii) The 30 coinsurance days;
(iii) The remaining lifetime reserve days.
(b) Posthospital SNF care furnished by a SNF, or by a hospital or a CAH with a swing-bed approval. Up to 100 days are available in each benefit period after discharge from a hospital or CAH. For the first 20 days, Medicare pays for all covered services. For the 21st through 100th day, Medicare pays for all covered services except for a daily coinsurance amount that is the beneficiary's responsibility.
(c) Renewal of inpatient benefits. The beneficiary's full entitlement to the 90 inpatient hospital or inpatient CAH regular benefit days, and the 100 SNF benefit days, is renewed each time he or she begins a benefit period. However, once lifetime reserve days are used, they can never be renewed.
(i) 80 percent of the reasonable cost of the service.
(ii) The reasonable cost of, or the customary charge for, the service, whichever is less, minus 20 percent of the customary (insofar as reasonable) charge for the service.
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