Medicare Prior Authorization: What Agents Need to Know

Prior authorization is one of the most common mid-year calls an agent gets, and it almost never comes at a convenient time. A client is scheduled for a procedure, the plan wants approval first, and they want to know whose fault it is.

You do not need to be an expert on utilization management. You need to know which rules apply to which product, what changed in 2026, and what to say next. That is all this guide covers.

The 30-second version

Original Medicare

For most of its history, Original Medicare has not used prior authorization in any meaningful way. A doctor orders the test, Medicare pays if it is medically necessary and properly documented.

That changed slightly on January 1, 2026. CMS launched a six-year pilot called the WISeR Model, short for Wasteful and Inappropriate Service Reduction. It applies prior authorization or pre-payment review to a short list of outpatient Part B services in six states: Arizona, New Jersey, Ohio, Oklahoma, Texas, and Washington. It runs through December 31, 2031.

The initial service list is narrow, covering things like skin substitutes for chronic wounds, certain orthopedic pain management procedures, and nerve stimulator implants. Provider participation is voluntary, and CMS requires a human clinician to review before any denial that involves automated technology.

What this means for you: If you write business in one of those six states, a Medicare Supplement client can now run into an approval step they have never seen before. It does not change which plan is right for them. It changes the expectation you set up front. Everywhere else, Original Medicare still works the way your clients expect.

Medicare Advantage

This is where almost every prior authorization conversation actually happens. Medicare Advantage plans must cover everything Original Medicare covers, but they are allowed to require approval first for many services, commonly imaging, surgeries, skilled nursing stays, and some specialist care.
Two federal rules give your clients real protections worth knowing by heart.

Faster decisions and a real reason for every denial

Beginning in 2026, Medicare Advantage plans must return prior authorization decisions within 72 hours for urgent requests and 7 calendar days for standard requests. For some plans, that cut the standard window in half. Plans must also state a specific reason for every denial. Vague denials are no longer acceptable. 

The 90-day switching protection

If a client is in the middle of an active course of treatment and moves to a new Medicare Advantage plan, the new plan must provide a minimum 90-day transition period and cannot require prior authorization for that active treatment during it. Separately, once a plan approves a course of treatment, that approval must stay valid for as long as the treatment is medically reasonable and necessary. 

What this means for you: That 90-day rule is your answer to the most common objection you will hear during AEP, which is some version of "I cannot switch, I am in the middle of treatment." They are protected. Confirm the specifics with the plan before you promise anything, then document the conversation.

It is also worth knowing that the major carriers have been publicly trimming their prior authorization lists. Health plans reported an 11 percent overall reduction and more than 15 percent in Medicare Advantage in the year following an industry-wide commitment.  The direction of travel is fewer requirements, not more. Check each carrier’s current list rather than working from memory. You can find the plans PSM contracts on the Medicare product portfolio.

Part D

Part D plans apply prior authorization to certain drugs on the formulary, usually high-cost, specialty, or brand-name medications. A related requirement is step therapy, where the client has to try a lower-cost drug first. If it fails or is not appropriate, the prescriber can request an exception.
Part D runs on its own clock. A plan must decide a standard coverage determination within 72 hours and an expedited one within 24 hours.  Note that the 2026 Medicare Advantage timelines above apply to medical items and services, not to Part D drugs. They are two different tracks, and mixing them up is an easy way to give a client the wrong expectation.

Medicare Supplement

Medigap plans do not have prior authorization. They pay their share of what Original Medicare approves, so they inherit Original Medicare’s rules and nothing more.

For clients who value predictability, that is a legitimate and factual point of difference, and one reason Medicare Supplement business stays steady year after year. Just state it accurately. Say Medigap has no prior authorization of its own. Do not say the client will never encounter an approval step, because in the six WISeR states that is no longer strictly true.

What to tell a client who gets denied

A denial is a starting point, not a verdict. Walk them through five steps.

1.    Get the specific reason in writing. Plans are required to provide one.

2.    Have the treating provider submit a letter of medical necessity with the clinical documentation.

3.    File the appeal within 60 calendar days of the denial notice. This deadline applies to   both Medicare Advantage reconsiderations and Part D redeterminations.

4.    Request an expedited appeal if waiting would seriously jeopardize their health. 

5.    If the plan upholds the denial, the case moves up. Medicare has five levels of appeal, and the second level goes to an independent review entity outside the plan. 

Emergency care is the exception to all of it. A Medicare Advantage plan cannot require prior authorization for emergency services. If a client is having an emergency, they go to the nearest emergency room.

Three things not to do

• Do not predict the outcome. You are not the plan’s medical reviewer. Explain the process and the timeline, not the answer.

• Do not file the appeal for them. The appeal belongs to the beneficiary and the treating provider. You point the way and follow up.

• Do not turn a denial into a switch pitch. Using one client’s bad experience to disparage a plan is a marketing compliance problem. Review the compliance guidelines for agents if you are unsure where the line sits.

The short version

Medigap has none. Original Medicare has almost none, plus a narrow new pilot in six states. Medicare Advantage has the most, on a faster clock, with a 90-day protection when clients switch mid-treatment. Part D has it for select drugs on its own 24 and 72 hour timelines. Denials get appealed within 60 days, and emergencies are always exempt.

Know those five sentences and you will handle almost every prior authorization call you get. If you are still building your foundation, start with the new agent training track. If you want help positioning this with a specific client, your PSM Sales Specialist can walk through it with you.

Sources

CMS — 2027 Medicare Advantage and Part D Enrollment Guidance
CMS — 2027 Medicare Advantage and Part D Rate Announcement
CMS — 2027 MA and Part D Final Rule
Modern Healthcare — Medicare Advantage enrollment caps promise to reshape 2027

This article is general education for licensed insurance agents. It is not legal, tax, or compliance advice. Plan-specific prior authorization requirements vary by carrier and by contract year. Always confirm current requirements directly with the plan.