Anesthesiologist Assistants (AAs)

Enroll in Medicare

For information on how to enroll in Medicare, visit Advanced Practice Non-Physician Practitioners.

Qualifications & Criteria

You must:

  • Work under anesthesiologist's direction
  • Comply with all applicable state laws, including state licensure requirements imposed on non-physician anesthetists
  • Have graduated from a medical school-based anesthesiologist assistant (AA) education program:
Service Requirements

You must meet these requirements:

  • You’re legally authorized to perform anesthesia and related care in the state where you provide the services.
  • In a hospital, you provide services under the supervision of an anesthesiologist who’s immediately available, if needed. Immediate supervision means an anesthesiologist is physically located within the same area as the AA and can provide immediate hands-on intervention.

  • In a critical access hospital or ambulatory surgical center (ASC), you provide services under the supervision of an anesthesiologist.

Billing Requirements
  • You may bill for your services using:
    • Your NPI
    • The hospital, physician, group practice, or ASC NPI where you have an employment or contractor relationship
  • Anesthesia time is the continuous period that:
    • Begins when you’ve prepared the patient for anesthesia services in the operating room or equivalent area
    • Ends when you place the patient safely under post-operative care
  • You may add blocks of anesthesia time if you provide continuous anesthesia care within the time periods around an interruption

    Anesthesia ModifierDescription
    QS

    Monitored anesthesia care service

    Note: A physician or qualified non-physician anesthetist may use the QS modifier for informational purposes. You must report actual anesthesia time and 1 payment modifier on the claim.

    QXCRNA service: with medical direction by a physician
    QY

    Medical direction of one certified nurse anesthetist (CRNA) by an anesthesiologist

    Note: Used by supervising physician.

    QZCRNA service: without medical direction by a physician

     

Payment Requirements
  • Medicare pays only on an assignment basis
  • We pay services at 100% under the Physician Fee Schedule or in accordance with the level of supervision provided
  • Under the Anesthesia Fee Schedule based on applicable locality adjusted anesthesia Conversion Factor (CF) multiplied by the sum of allowable base and time units; 1 anesthesia time unit = 15 minutes anesthesia time
  • The patient may be responsible for paying you for a Medicare Part B copayment, deductible, or coinsurance
  • We may pay you directly or pay another individual or entity where you have an employment or contractual arrangement

More Information

 

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Page Last Modified:
05/13/2026 12:15 PM