42 CFR § 417.454 - Charges to Medicare enrollees.
(a) Limits on charges. The HMO or CMP must agree to charge its Medicare enrollees only for the—
(1) Deductible and coinsurance amounts applicable to furnished covered services;
(2) Charges for noncovered services or services for which the enrollee is liable as described in § 417.452; and
(3) Services for which Medicare is not the primary payor as provided in § 417.528.
(b) Limit on charges for inpatient hospital care. If a Medicare enrollee who is an inpatient of a hospital requests immediate QIO review (as provided in § 417.605) of any determination by the hospital furnishing services or the HMO or CMP that the inpatient hospital services will no longer be covered, the HMO or CMP may not charge the enrollee for any inpatient care costs incured before noon of the first working day after the QIO issues its review decision.
(c) Reporting requirements. A risk HMO or CMP must report, within 90 days after the end of the contract period, all premiums, enrollment fees, and other charges collected from its Medicare enrollees during that period.
(d) Limit on charges for specified preventive services. An HMO may not charge deductibles, copayments, or coinsurance for in-network Medicare-covered preventive services (as defined in § 410.152(l)).
(e) Services for which cost sharing may not exceed cost sharing under original Medicare. On an annual basis, CMS will evaluate whether there are service categories for which HMOs' cost sharing may not exceed that required under original Medicare and specify in regulation which services are subject to that cost sharing limit. The following services are subject to this limit on cost sharing:
(1) Chemotherapy administration services to include chemotherapy drugs and radiation therapy integral to the treatment regimen.
(2) Renal dialysis services as defined at section 1881(b)(14)(B) of the Act.
(3) Skilled nursing care defined as services provided during a covered stay in a skilled nursing facility during the period for which cost sharing would apply under Original Medicare.
(4) A COVID-19 vaccine and its administration described in section 1861(s)(10)(A) of the Act.