CMS has expanded prior authorization requirements under the Medicare fee-for-service program. These requirements apply to certain high-utilization, high-cost services where improper payments have been identified.
Services subject to prior authorization
The following service categories are currently subject to Medicare prior authorization requirements (the specific codes covered expand periodically — check your MAC’s website for the current list):
- Certain outpatient hospital procedures (selected OPPS services)
- Repetitive non-emergency ambulance transports (see EMS billing update)
- Home health services (in demonstration states)
- Certain durable medical equipment items
How to submit a prior authorization request
Prior authorization requests are submitted to the beneficiary’s MAC. Submission methods vary by MAC — most accept electronic submission via their portal, fax, or mail.
A complete request includes:
- The beneficiary’s Medicare ID number
- The ordering provider’s NPI and contact information
- The procedure code(s) requiring authorization
- Supporting clinical documentation establishing medical necessity
- The anticipated service date
Provisional Affirmation vs. Non-Affirmation
MACs issue either a Provisional Affirmation (PA) or Non-Affirmation (NA). A PA means the service may be provided and billed. A NA means CMS identified a medical necessity concern — it is not a coverage denial, but services provided without resolving the NA are subject to claim-level review and likely denial.
⚠️ Risk flag: A prior authorization is not a guarantee of payment. Claims can still deny post-authorization for issues unrelated to the PA (e.g., billing errors, eligibility issues, duplicate claims).
Appealing a Non-Affirmation
A NA can be appealed or resubmitted with additional documentation. The most effective approach is to address the specific reason for the NA — MACs are required to provide a reason code — and resubmit with additional supporting documentation.
Ask Mae if you have a specific prior authorization question for your service type.