Anesthesia

Teaching Anesthesiology Services

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Teaching Anesthesiology Services

Payment may be made under the Medicare physician fee schedule at the regular fee schedule level if the teaching anesthesiologist is involved in the training of a resident in a single anesthesia case, two concurrent anesthesia cases involving residents, or a single anesthesia case involving a resident that is concurrent to another case paid under the medical direction rules.

To qualify for payment, the teaching anesthesiologist, or different anesthesiologists in the same anesthesia group, must be present during all critical or key portions of the anesthesia service or procedure involved. The documentation in the patient’s medical records must indicate the teaching physician’s presence during all critical or key portions of the anesthesia procedure and the immediate availability of another teaching anesthesiologist as necessary. 

The teaching anesthesiologist (or another anesthesiologist with whom the teaching physician has entered into an arrangement) must be immediately available to furnish anesthesia services during the entire procedure. If different teaching anesthesiologists are present with the resident during the key or critical periods of the resident case, the NPI of the teaching anesthesiologist who started the case must be indicated in the appropriate field on the claim form or electronic equivalent.

The teaching anesthesiologist should use the “AA” modifier and the “GC” certification modifier to report such cases.

Modifier Narrative
AA Anesthesia service personally performed by anesthesiologist
GC Services performed by a resident under the direction of a teaching physician ‒ provider must also use one of the other payment modifiers


The teaching anesthesiologist must document involvement in cases with residents. The documentation must be sufficient to support the payment of the fee and available for review upon request.

Use modifier GC (teaching physician service) to indicate the service has been performed in part by a resident under the direction of a teaching physician. This modifier is added after the anesthesia procedure code.

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Anesthesia Services and Teaching CRNA

The AANA indicates that their standards for approved nurse anesthetist training programs allow teaching CRNAs to supervise two concurrent cases involving student nurse anesthetists.

Payment can be made under Medicare Part B to a teaching CRNA who supervises a single case involving a student nurse anesthetist where the CRNA is continuously present. The CRNA reports the service using the usual “QZ” modifier.

The teaching CRNA must document involvement in the cases with the student nurse anesthetists.

Modifier Narrative
QZ CRNA service: without medical direction by a physician
GC Services performed by a resident under the direction of a teaching physician ‒ provider must also use one of the other payment modifiers


Modifier QZ designates that the teaching CRNA is not medically directed by a physician anesthesiologist and the use modifier GC (Teaching Physician Service) indicates the service has been performed in part by a student nurse anesthetist under the direction of a teaching CRNA. Modifier GC is added after the anesthesia modifier.

  • Payment is allowed for the full-base units (assigned to the anesthesia code) where the teaching CRNA is present with the student nurse anesthetist throughout pre and post anesthesia care
  • Payment is allowed for the actual time the teaching CRNA is personally present with the student nurse anesthetist
  • Anesthesia time may be discontinuous

For example, a teaching CRNA is involved in two concurrent cases with student nurse anesthetists. Payment is allowed for the actual time the CRNA is personally present with the student nurse anesthetist:

Case # Time Spent Total Time Quantity Billed
1 10:15‒10:30 a.m. (15 minutes) 45 Minutes 00030
2 9:45‒10:14 a.m. (29 minutes)
10:31‒11:30 a.m. (59 minutes)
88 Minutes 00059


The teaching CRNA must document involvement in the cases with the student nurse anesthetists. No payment is made under Medicare Part B for the service provided by a student nurse anesthetist.

The documentation must be sufficient to support the payment of the fee and available for review upon request.

To bill the anesthesia base units, the CRNA must be present with the student nurse anesthetist during the pre and post anesthesia care for each of the two cases. To bill anesthesia time for each case, the teaching CRNA must continue to devote time to the two concurrent cases and not be involved in other activities.

The teaching CRNA can decide how to allocate time to optimize patient care in the two cases based on the complexity of the anesthesia case, the experience and skills of the student nurse anesthetist, the patient’s health status and other factors.

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Physician Personally Performed and Personally Performed with CRNA and AA

The following applies to anesthesia services personally performed:

  • The physician personally performed the entire anesthesia service alone
Modifier Narrative
AA Physician personally performs
  •  
  • The physician is involved with one anesthesia case with a resident and the physician is a teaching physician
  • The physician is involved in the training of physician residents in a single anesthesia case, two concurrent anesthesia cases involving residents, or a single anesthesia case involving a resident that is concurrent to another case paid under the medical direction rules
  • The physician is continuously involved in a single case involving a student nurse anesthetist
  • If the physician is involved with a single case with a CRNA (or AA) contractors may pay the physician service and the CRNA (or AA) service in accordance with the medical direction payment policy
  • The physician and the CRNA (or AA) is involved in one anesthesia case and the services of each are found to be medically necessary
Modifier Narrative
AA Physician personally performs
GC Services performed by a resident under the direction of a teaching physician ‒ provider must also use one of the other payment modifiers
QX CRNA with medical direction by a physician
QY Medical direction of one qualified nonphysician anesthetist by an anesthesiologist

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Revised 11/16/2023