Anesthesia Modifiers: A Lowdown on the Basics

With so many different codes for each medical procedure and several modifiers indicating special circumstances under which the procedure was performed, documenting everything properly is a tough task for billers. Especially so when it comes to anesthesia services— since anesthesia modifiers are the trickiest and often confuses billers leading to misuse.

Anesthesia modifiers indicate which medical professional was administering the services, and these conditions determine at what rate the services are billed. Therefore, it’s imperative for healthcare professionals to get educated about medical bill coding and review the bills properly to ensure incorrect charges are corrected.

Here’s a lowdown on the basics of anesthesia modifiers for medical bill coding:


Modifier Description


One of the following modifiers must be reported with anesthesia services in the first modifier field to indicate who performed the anesthesia service.


  • Modifier AA – Anesthesia services performed personally by an anesthesiologist.


  • Modifier QK – Medical direction by a physician of two, three, or four concurrent anesthesia procedures.


  • Modifier AD – Medically supervised by a physician, more than four concurrent anesthesia procedures.


  • Modifier QY – Medical direction of one CRNA/AA (Anesthesiologist’s Assistant) by an anaesthesiologist


  • Modifier QX – CRNA/AA (Anesthesiologist’s Assistant) service with medical direction by a physician.


  • Modifier QZ – CRNA service without medical direction by a physician.


The following modifiers can be reported in the 2nd position under appropriate circumstances in addition to one of the previous anesthesia modifiers:

Modifier Description
QS Monitored anesthesia care service
23 Unusual anesthesiaNote: When using modifier 23, appropriate documentation must be submitted with the claim.
33 Preventive Services: When the primary purpose of the service is the delivery of an evidence based service in accordance with a US Preventive Services Task Force A or B rating in effect and other preventive services identified in preventive services mandates (legislative or regulatory), the service may be identified by adding 33 to the procedure.


Correctly using the appropriate modifiers can save you thousands of dollars in RAC audits for anesthesia repayments and penalties. For more insights on Anesthesia Modifiers, check these audio sessions by AudioEducator with some of the leading U.S. healthcare experts.

Leave a Reply

Your email address will not be published. Required fields are marked *