Prior authorization under Medicare Advantage

Medicare Advantage, also called Medicare Part C, is the private-plan alternative to Original Medicare. A beneficiary enrolls with a health plan that contracts with CMS to deliver Part A and Part B benefits, often bundled with Part D drug coverage, in a single package. The plan is paid to manage that care, and it administers benefits using utilization-management tools — including prior authorization — that Original Medicare largely does not apply. Under Original Medicare, most Part A and Part B services are paid after the fact without advance approval, aside from a limited set of exceptions. The routine use of prior authorization is therefore one of the most operationally significant differences a practice encounters when a patient's coverage is a Medicare Advantage plan rather than Original Medicare, and confirming which one applies begins with eligibility verification, including verifying Medicare eligibility and verifying the plan type.

The clearest way to see where prior authorization fits is to compare the two ways Medicare benefits are delivered across the dimensions that matter for revenue-cycle work.

Although Medicare Advantage plans design their own utilization-management programs, they operate inside a federal framework that CMS enforces. A plan's coverage criteria for basic benefits generally cannot be more restrictive than Original Medicare, so a service that Traditional Medicare would cover cannot be excluded by a plan's internal rule alone. A plan may create its own internal coverage criteria only where Medicare's own criteria are not fully established, and those criteria must be based on current evidence drawn from widely used treatment guidelines or clinical literature and must be made publicly accessible along with the evidence and rationale behind them. A determination of medical necessity remains the substantive basis for an approval or a denial. Those limits are enforced inside the plan by a committee: a plan may not apply any utilization-management policy that the Medicare Advantage utilization management committee has not reviewed and approved, and the regulation states what that committee is permitted to approve.

Federal rules also shape the process itself. The CMS Interoperability and Prior Authorization rule adds requirements such as specific decision timeframes, communication of the reason for a denial, public reporting of authorization metrics, and electronic prior-authorization interfaces that phase in over a defined schedule. These requirements evolve through rulemaking, so the current CMS materials — not older summaries — should be treated as the source of truth.

In Medicare Advantage terminology, a request to approve coverage before a service is furnished is part of an organization determination — the plan's decision about whether it will pay for an item or service. Requests generally follow either a standard track or an expedited track, the latter used when applying the standard procedure could seriously jeopardize the patient's life, health, or ability to regain maximum function. CMS sets the maximum timeframes a plan may take for each track; because those limits are fixed by regulation and can be amended, the exact windows should be read from the current CMS source rather than assumed. For certain physician-administered drugs a plan may also apply step therapy, and medication prior authorization follows its own plan-specific pathway.

1. 01

   Confirm the plan

   Verify that the patient is enrolled in a Medicare Advantage plan and identify the specific plan, because requirements differ from one plan to the next.
2. 02

   Identify the requirement

   Check the plan's current authorization list to determine whether the planned service requires an organization determination.
3. 03

   Submit the request

   Send the request with the clinical documentation that supports medical necessity, following the plan's channel and format as described in the authorization workflow.
4. 04

   Track the decision

   Monitor the standard or expedited determination and record the authorization number once it is issued.
5. 05

   Reconcile at billing

   Match the approved service and units to what is billed so the claim aligns with the authorization.

When a plan issues an adverse organization determination, the result is a denial of coverage that can be challenged. Medicare Advantage has its own multi-level appeal process that differs from Original Medicare's: it begins with a reconsideration by the plan and, if the plan upholds the denial, moves to review by an independent entity that contracts with CMS, with further levels beyond that. Where a plan offers a peer-to-peer review, the ordering clinician discusses the case with the plan's medical reviewer before or during an appeal.

Determining whether a specific denial is authorization-related — as opposed to an eligibility or coding problem — drives the correct response. Guidance on reading the plan's reason and choosing a path is covered in approvals, denials, and peer-to-peer review and in authorization-related denials.

For a billing operation, the practical takeaway is that Medicare Advantage cannot be treated as interchangeable with Original Medicare. Requirements are plan-specific, they change, and a missing authorization typically cannot be cured after the service is furnished.

• Verify Medicare Advantage enrollment and the exact plan at each encounter, since a patient can change plans between years.
• Confirm the plan's current authorization requirements rather than relying on a prior year's list.
• Obtain the organization determination before the service whenever the plan requires it, and use urgent or retroactive pathways only where the plan allows them.
• Record the authorization number and reconcile approved units against billed services.
• Distinguish Medicare Advantage requirements from those under Medicaid, which follows a separate framework.