Ambulatory Surgical Center Prior Authorization Services

Published 10/06/2025

Prior authorization helps Ambulatory Surgical Center (ASC) providers ensure services comply with applicable Medicare coverage, coding, and payment rules before rendering the service and submitting a claim for payment.

Timeline

On December 15, 2025, CMS will start a 5-year prior authorization demonstration for certain services provided in ASCs in Ohio, Arizona, California, Florida, Georgia, Maryland, New York, Pennsylvania, Tennessee, Texas.

Beginning on December 1, 2025, ASCs can submit prior authorization requests for dates of service on or after December 15, 2025.

ASC Services (HCPCS Codes)

See the full list of HCPCS codes for prior authorization.

Prior authorization for the ASC demonstration is voluntary. However, if you elect to bypass prior authorization, applicable ASC claims are subject to prepayment medical review.

Request Types & Timeframes

When completing the prior authorization request (PAR) form, select the appropriate request type and allow the allotted timeframe for Palmetto GBA to issue a decision.

Request Type Description Review Decision Timeframe

Initial

First PAR submission for this beneficiary/date of service.

NOTE: A PAR is valid for one claim/date of service.

7 calendar days

Resubmission

Any subsequent PAR submission (i.e., to correct an error or omission after receiving a non-affirmation decision for an initial PAR). Providers have an unlimited number of opportunities to resubmit a PAR.

NOTE: Report the most recent Unique Tracking Number (UTN) with each resubmission request.

7 calendar days

Expedited

Used ONLY when a delay for a decision could seriously jeopardize the beneficiary's life, health or ability to regain maximum function.

NOTE: Don't select this request type based solely on the scheduled procedure date. If appropriate, you must include the specific reason/rationale for Palmetto GBA to substantiate the need for an expedited decision.

2 business days

Decision Letter(s)

Palmetto GBA will send a decision letter with the UTN to:

  • The requester (via the same method used to submit the PAR)
  • A fax number provided in the PAR (optional)
  • The beneficiary

NOTE: While the prior authorization process applies to ASCs, CMS allows a physician or practitioner to submit a PAR on the ASC’s behalf. The requester is responsible for communicating the decision/UTN to the appropriate provider(s).

Decisions

A valid PAR will result in one of the following decisions. A PAR decision and associated UTN is valid for 120 days from the decision letter date.

Decision Description

Provisional Affirmation

A preliminary finding that a future claim submitted to Medicare for the service(s) likely meets Medicare's coverage, coding and payment requirements.

Non-Affirmation

A preliminary finding that a future claim submitted to Medicare for the requested service does not likely meet Medicare's coverage, coding and payment requirements.

NOTE: Palmetto GBA will provide an explanation for a non-affirmative decision. You may submit a resubmission request with additional/updated documentation until you receive a provisional affirmation decision.

Provisional Partial Affirmation

One or more service(s) on the PAR received a provisional affirmation decision and one or more service(s) received a non-affirmation decision.

Unique Tracking Number (UTN)

Report the UTN on the ASC claim only.

  • For electronic claims, report the UTN in the 2300 Claim Information loop in the Prior Authorization reference (REF) segment where REF01 = G1 qualifier and REF02 = UTN.
  • For paper claims, the UTN must populate the first 14 positions in item 23. All other data submitted in item 23 must begin in position 15.

Affirmed PA Decision on File

If the UTN reported on a claim corresponds with a provisional affirmation decision, including any service(s) that was part of a partially affirmed decision, the claim:

  • Will likely pay if all Medicare coverage, coding and payment requirements are met.
  • May deny based on either of the following:
    • Technical requirements that are only evaluated after claim submission
    • Information not available at the time of the PAR
  • Is afforded some protection from future audits (pre- and postpayment); however, review contractors may audit claims if potential fraud, inappropriate utilization or changes in billing patterns are identified.

Non-Affirmed PA Decision on File

If the UTN reported on a claim corresponds with a non-affirmation decision, including any non-affirmed service(s) that was part of a partially affirmed decision:

  • The claim will deny.
  • All appeal rights are then available.
  • You may then submit the claim to secondary insurance, if applicable.

No PA Decision on File

Claims for a service that requires prior authorization without a UTN:

  • Don’t require any information in the remarks field or any unsolicited documentation upon claim submission.
  • Palmetto GBA will suspend the claim and send the ASC an Additional Documentation Request (ADR) letter.
  • The ASC should submit all requested documentation within 45 days. If Palmetto GBA doesn’t receive a response by day 46, the claim will deny for non-receipt of records.
  • Palmetto GBA will review the documentation and make a claim determination within 30 days.

Claim Exclusions

Claim types excluded from the prior authorization program include:

  • Veterans' Affairs
  • Indian Health Services
  • Medicare Advantage
  • Medicare Advantage IME only claims
  • Railroad Retirement Board

Appeals

Claims subject to prior authorization under the ASC demonstration follow all current appeals procedures. A non-affirmed PAR decision isn't appealable since it's not an initial determination on a claim for payment for services provided. Providers have an unlimited number of opportunities to resubmit a PAR before submitting a claim.

A non-affirmation decision doesn't prevent the provider from submitting a claim. Submission of such a claim and resulting denial does constitute an initial payment determination, which makes the appeal rights available.

A claim submitted without a UTN has appeal rights if the prepayment medical review decision is a denial.

See the CMS Medicare Claims Processing Manual (Pub. 100-04), chapter 29 for additional information.

Resources

Operational Guide (PDF)

Frequently Asked Questions (PDF)


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