Medicare may require healthcare providers to obtain prior authorization for a service, procedure, prescription drug, or a piece of durable medical equipment (DME) the provider is recommending. If prior authorization is required, and your healthcare provider fails to obtain it, there will be no coverage for the service needed, and if you proceed with the provider’s recommendation, you will have to pay for it yourself.

The healthcare provider ordering the service always takes care of the paperwork required since the form requires information from the provider as well as the provider’s signature. The provider will send the form directly to Medicare.

Does Original Medicare Require Prior Authorization for Part A Services?

Usually, your physician or hospital will take charge of sending the forms to Medicare and obtaining prior authorization on your behalf. However, it is still important to note the following:

  • Original Medicare rarely requires prior authorization for inpatient hospital services under Part A.
  • Prior authorization is often required for DME and prosthetics.
  • Care in a skilled nursing facility or hospice do not require prior authorization as long as certain conditions are met including the provider’s explanation of why the services are medically necessary.

Does Original Medicare Require Prior Authorization for Medicare Part B?

Just as explained in Medicare Part A, the same goes for Medicare Part B. If prior authorization is needed your doctor will take care of sending the request to Medicare, when approved the procedure or drug will be covered. Medicare Part B works slightly different than Medicare Part A:

  • Original Medicare does not generally require prior authorization for medically necessary services provided under Part B. This also applies to the administration of certain drugs that are given in an outpatient setting.
  • Diagnostic tests a physician orders as medically necessary usually do not require prior authorization.
  • Medicare considers services required to diagnose, treat, or prevent a medical condition are medically necessary.
  • There are some procedures that are often considered to be cosmetic, or for some other reason, Medicare requires prior authorization.

Medicare provides a list of these procedures to help both you and your healthcare provider know how to proceed.

Does Medicare Require Prior Authorization for Services Provided by Medicare Advantage Plans Under Part C?

Each Medicare Advantage plan is different be aware of the following rules:

  • You most likely will need prior authorization for coverage of out-of-network and specialist care.
  • Services that commonly require prior authorization are approval of Part B drugs, DME, and stays at skilled nursing facilities.
  • If Medicare does not approve the request, your Advantage plan will typically not provide coverage. If you continue with the recommended care, you will have to pay the full cost.
  • Advantage plans do have a provision allowing you to appeal to the plan administrator if coverage is denied.

In most cases, your healthcare provider is the one responsible for obtaining prior authorization. If your healthcare provider says Medicare puts that burden on you, you can find the prior authorization forms online.

Does Medicare Require Prior Authorization for Prescription Drugs Under Part D?

To have coverage for your prescription drugs, you must sign up for a Medicare drug plan under Part D. Most Medicare Advantage plans include Part D coverage in their plans that cover both Part A and Part B prescription drugs.

If your physician or pharmacist tells you that you need prior authorization for your prescription drug, you can download the form here and provide it to your doctor. The doctor has the information needed to complete the form and must sign it. If Medicare still denies coverage, there is an appeal process.


  1. Prior Authorization and Pre-claim Review Initiatives, CMS. 
  2. Outpatient Department Services That Require Prior Authorization, CMS.
  3. How to Get Prescription Drug Coverage, Medicare.
  4. Appeals Overview, CMS.