General Introduction to Anesthesia coding – PART 3

Anesthesia modifiers:Modifiers are an important part of the medical coding and billing process. In Anesthesia coding, nearly every code billed is appended with a modifier. The incorrect use of modifiers would result in erroneous billing to the Anesthesia providers. Therefore coders should be cautious when appending modifiers to the Anesthesia claims.

As already discussed in the earlier introduction parts, there are two types of Anesthesia modifiers:

1. Anesthesia pricing modifiers (payment modifiers)

2. Informational modifiers

1. Anesthesia pricing modifiers:

An Anesthesia service can be performed by either Anesthesiologist or CRNA or both. The following anesthesia pricing modifiers direct prompt and correct payment of claims by indicating who actually performed the anesthesia service. These modifiers should be billed in the first modifier field.

Modifier Information billed by an Anesthesiologist:

  • AA: Anesthesia services personally performed by the Anesthesiologist
  • AD: Medical supervision by a physician, more than four concurrent procedures.
  • QK: Medical direction of two, three or four concurrent anesthesia procedures.
  • QY: Medical direction of one CRNA by an Anesthesiologist.

Modifier Information billed by a CRNA:

  • QX: CRNA service; with medical direction by a physician.
  • QZ: CRNA service; without medical direction by a physician.

If you want to assign all the above modifiers, you must also know about the key terms such as “personally performed”, and “medical supervision” and medical direction. A complete understanding of these terms is essential to append the correct modifiers to the Anesthesia claims.

Personally Performed Services: (AA modifier)

Under Medicare regulations, an anesthesia procedure is considered “personally performed” by the anesthesiologist:

  • If the physician is continuously involved in a single case.
  • The physician may not leave the operating room to perform other medical procedures.
  • The anesthesiologist must remain physically present in the operating room during the entire procedure.

Note: If the anesthesiologist is not continuously involved with the case, then it is not considered a personally performed service and should be reported using the medical direction modifiers.

Medical Direction: (QK, QY and QX)

Medical direction occur when an anesthesiologist is involved in directing the anesthesia care provided by a certified registered nurse anaesthetist (CRNA) or a physician assistant (PA) trained in anesthesia. Successful coding of medical direction relies on compliance with seven elements listed as below:

  • Performs the pre-anesthesia examination and evaluation
  • Prescribes the anesthesia plan
  • Personally participates in the most demanding
  • procedures of the anesthesia plan, including induction and emergence
  • Ensures that any procedures in the anesthesia plan that he/she does not perform are performed by a qualified individual
  • Monitors the course of anesthesia administration at intervals
  • Remains physically present and available for immediate diagnosis and treatment of emergencies
  • Provides indicated post-anesthesia care

If any of the seven steps for medical direction is not performed or a procedure that is not allowed under medical direction is performed, then it will be designated as medical supervision which will result in a lower reimbursement.

Medical Supervision: (AD modifier)

An Anesthesiologist service is considered medical supervision:

  • If an anesthesiologist is involved in more than four concurrent anesthesia procedures with a qualified non-physician anesthetist, or
  • When the anesthesiologist cannot perform all seven required services under medical direction regardless of the number of concurrent anesthesia procedures.

Under medical supervision, the anesthesia service is billed under the anesthesiologist with the AD modifier. Claims for anesthesia services using modifier AD allows for three base units per procedure and an additional time unit can be recognized if the physician documents that they were “present on induction”.

2. Anesthesia Informational Modifiers

Anesthesia informational modifiers are for information only and should be included after the pricing modifiers. While there are no units or monetary value associated with these modifiers, they are used only to emphasize increased complexity, risk and/or comorbid conditions such that anesthesia services were considered medically necessary in that case.

  • QS – Monitored anesthesia care service
  • G8 Monitored Anesthesia Care (MAC) for deep complex, complicated or markedly invasive surgical procedure.
  • G9 Monitored Anesthesia Care (MAC) for patient who has history of severe cardiopulmonary condition
  • P1–P6 Anesthesia Physical Status Modifiers

Postoperative Pain Procedures in conjunction with Anesthesia:

Postoperative pain management services are generally provided by the surgeon who is reimbursed under a global payment policy related to the procedure. However many surgeons requests the anesthesiologist to perform these services due to their efficiency in pain management.

POPM (Post-operative pain management services) can be billed by the Anesthesia practitioner only when the documentation satisfies the below elements:

Documentation requirements:

  • Administer the post-operative pain block per a surgeon’s request. This must be specified in the medical record.
  • Document the time spent administering the block separately from the anesthesia time. Attach a modifier -59 to the block CPT codes when applicable.
  • Document the method for administering the block separately from the method for administering the surgical anesthesia (usually via a separate section in an EHR or separate block record).
  • Indicate the purpose or the reason for the block, as well as the specific site of pain. Example: “Interscalene block administered for post-op pain management for shoulder pain per surgeon’s request”.
  • Indicate the type of block or catheter that was performed.(single or continuous catheter)
  • Description of the block procedure (patient prep, topical anesthesia used, a short description of the block procedure performed.
  • If imaging is used, document retention of images as appropriate (“Images retained”).
  • Date and legible signature.

Finally, we have completed the three parts in “GENERAL INTRODUCTION TO ANESTHESIA CODING”. If you have any queries please mail to


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