Whether you’re filling a prescription or scheduling a procedure, chances are you’ve been asked whether you have prior authorization. By learning to navigate prior authorization and what steps to take if your health care service is denied, you can better maneuver the complexities of care.
[READ: How to Use AI to Help Fight a Health Insurance Denial: Step-by-Step Guide]
What Is Prior Authorization?
Prior authorization is approval from a health plan to ensure a service, prescription or other benefit is medically necessary. When your doctor orders a service, such as a diagnostic test, routine procedure or prescription medication, that may require a prior authorization, they must send a request for approval.
This requirement has been widely adopted by the insurance industry to control health care costs.
“While prior authorization has long been used as a tool to contain spending and prevent people from receiving unnecessary or low-value services, there are some concerns that current prior authorization requirements and processes may create barriers and delays to receiving necessary care, as well as exacerbate complexity for patients and their providers,” explains Jeannie Fuglesten Biniek, an associate director for the Program on Medicare Policy at KFF.
| Medicare Type | Prior Authorization Usage | Services Requiring Prior Authorization | Notes |
|---|---|---|---|
| Original Medicare (Part A and Part B) | Used sparingly for specific items/services |
— Hospital outpatient procedures — Durable medical equipment — Inpatient rehabilitation |
Rarely required, but exceptions exist for high-cost or fraud-prone services |
| Medicare Part D (Prescription Drugs) | Typically used for higher-tiered drugs. Also known as a “coverage determination.” | Higher-tiered medications, such as brand-name or specialty drugs. | Often involves step therapy where lower-cost drugs must be tried first before the plan approves coverage for a more expensive alternative |
| Medicare Advantage | Used commonly to control costs (99% of enrollees are in plans requiring prior authorization) |
— Skilled nursing facility stays — Part B drugs — Inpatient hospital care — Outpatient psychiatric services — Out-of-network care — Specific tests (e.g., MRI) — Visits to a specialist |
Most common use of prior authorization, encompassing nearly all high-cost and many routine services |
[READ: Medicare vs. Medicare Advantage: How to Choose.]
Medicare and Prior Authorization
Currently, original Medicare (Part A and Part B) rarely requires prior authorizations. However, to contain costs, the Centers for Medicare & Medicaid Services (CMS) has authorized Medicare to require prior authorizations for certain hospital outpatient procedures, durable medical equipment and preapproval for inpatient rehabilitation and home health services.
Common procedures or equipment that require prior authorization include:
Durable medical equipment
— Infusion pump systems
— Leg braces
— Wheelchairs and accessories
Hospital outpatient services
— Body contouring surgery to remove excess skin and fat
— Cervical fusion with disc removal
— Eyelid surgery
— Facet joint interventions to treat chronic pain in the neck or lower back
— Implanted spinal neurostimulators
— Nose reconstruction
— Vein ablation
To see the full list, visit the CMS website.
How is Medicare prior authorization changing in 2026?
Beginning in 2026, the CMS has announced it will implement prior authorization requirements for certain services in six states — Arizona, New Jersey, Ohio, Oklahoma, Texas and Washington. According to the CMS, this new cost-effective model, known as the WISeR (Wasteful and Inappropriate Service Reduction) model, is testing the use of advanced technologies, including AI, combined with human clinical oversight on the prior authorization process for certain services that are especially prone to fraud, waste, abuse or inappropriate use.
These services include:
— Incontinence control devices
— Electrical nerve stimulator implants
— Knee arthroscopy for osteoarthritis
— Epidural steroid injections for pain management
The model excludes:
— Inpatient-only procedures
— Any care that could pose serious risks to patients if delayed
The CMS emphasizes that while technology will assist in the review process, final decisions to deny a request will be made by licensed clinicians.
In addition, starting January 1, 2026, the CMS has directed that Medicare Advantage plans, Medicaid and the Medicare plans in the six states participating in the WISeR model resolve prior authorization requests for routine services within seven days. For urgent requests, plans must resolve prior authorization requests within 72 hours.
[READ: Does Medicare Cover Mental Health Treatment?]
Medicare Part D and Prior Authorization
In Medicare Part D, prior authorization can also be referred to as a coverage determination. Medicare Part D plans use a drug tier system to organize medications based on cost and type, with lower tiers, like tier 1, generally covering low-cost generics and higher tiers, like Tier 4 or 5, including more expensive brand-name or specialty drugs.
Coverage determinations are typically required only for the higher-tiered medications, such as Wegovy or Jardiance. The approvals process may also involve step therapy, which requires you to try a lower-cost medication first before the plan approves coverage for a more expensive alternative.
Medigap and Prior Authorization
Under Medigap plans, prior authorizations are not required. However, if original Medicare requires prior authorization for a specific service, then that requirement must be met before Medigap will cover its portion of the costs. Medigap policies are designed to cover the “gaps” in original Medicare, such as copayments, coinsurance and deductibles that individuals would otherwise be responsible for paying.
“Medigap policies only pay for services that are approved by original Medicare,” says Marcia Mantell, founder and owner of Mantell Retirement Consulting in Plymouth, Massachusetts. “If Medicare covers a service and it doesn’t require prior authorization, then the Medigap policy will also cover its share without needing prior authorization.”
Medicare Advantage and Prior Authorization
While prior authorizations are used sparingly by original Medicare and Medigap, it is a common approach to controlling costs for Medicare Advantage plans.
In 2025, nearly all Medicare Advantage enrollees (99%) were in plans that require prior authorization for certain services, according to KFF. This requirement is most common for higher-cost services, including skilled nursing facility stays (99%), Part B drugs such as chemotherapy or IV antibiotics (98%), inpatient hospital care (acute: 96%; psychiatric: 93%) and outpatient psychiatric services (80%). In contrast, preventive services rarely require prior authorization (only 7%).
In addition to prior authorization for specific treatments, Medicare Advantage plans may also require prior authorization for receiving out-of-network care, getting a specific test like an MRI or seeing a specialist.
Illustrating how Medicare Advantage plans rely on prior authorizations, in 2023, Medicare Advantage insurers made nearly 50 million prior authorization determinations, while in contrast 400,000 prior authorizations were submitted to the CMS for original Medicare, KFF reports. Despite having a similar number of enrollees, Medicare Advantage plans averaged two prior authorizations per enrollee while original Medicare averaged one per 100 enrollees.
How to Navigate Prior Authorizations
It’s important to understand what is covered by your plan to avoid any surprises and denial of benefits.
Here are some tips on how to navigate your health insurance and prior authorizations:
— Check plan details. If you have Medigap, Medicare Advantage or Medicare Part D prescription drug coverage plan, review your plan’s specific requirements for prior authorization. For example, with continuous glucose monitors, original Medicare does not require prior authorization as long as the CMS criteria is met. Most Medicare Advantage plans, on the other hand, do require prior authorization for the device and supplies unless you have Type 1 diabetes. These details are usually available in your plan’s summary of benefits materials.
— Consult your doctor. Work with your health care provider to ensure that any necessary prior authorizations are obtained before services are needed. Typically, the doctor’s office will handle the paperwork and submission process.
— Contact your insurer. If you are unsure whether a service requires prior authorization, contact your plan’s customer service for more information. Medicare Advantage plans may change from year to year, and it’s important to verify that a medication or needed service will still be covered in the upcoming year.
— Appeal denials. If a prior authorization request is denied, you have the right to appeal the decision. Your doctor can help you with this process by providing additional medical justification, and you will often have to contact the health plan to initiate the appeals process, which may take a few days to more than a week, depending on the plan. It can pay off to appeal a denial, as just 11% of denied Medicare Advantage prior authorization requests in 2023 were appealed, but 81% of them were partially or fully overturned, KFF notes.
“It’s hard to pinpoint why this rate is so low,” Fuglesten Biniek says. “It could be that the process is too difficult, that people don’t understand how to appeal, don’t have the resources or time to do so, especially because they often come at a time when they are most vulnerable because of illness or injury.”
Bottom Line
Prior authorizations are used to curtail health care costs and are sparingly used by original Medicare for certain procedures, equipment and services. In 2026, however, the CMS is testing a new prior authorization process model in six states for certain services in original Medicare that, if successful, could be rolled out nationally.
There are no separate prior authorization requirements under a Medigap policy beyond the limited cases where Medicare requires prior authorization. However, Medicare Advantage plans heavily rely on using prior authorizations, especially for the most expensive health care services. If a prior authorization is denied, individuals can appeal the process directly or seek the help of your doctor’s office to provide further medical justification.
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Does Medicare Require Prior Authorization? originally appeared on usnews.com
Update 03/06/26: This story was previously published at an earlier date and has been updated with new information.