MAC and medical necessary documents with modifier using

Appropriate documentation must be available to reflect pre- and post-anesthetic evaluations and intra-operative monitoring.

The MAC service rendered must be reasonable, appropriate and medically necessary.


The anesthesia procedures listed in the LCD are examples of those that are usually provided by the attending surgeon and are included in the global fee and are not separately billable. In certain instances, however, MAC provided by anesthesia personnel, may be necessary for these procedures if the patient has one or more of the conditions or situations found in the ICD-9-CM Codes That Support Medical Necessity in the LCD. MAC may be necessary for these active and serious accompanying situations or conditions to ensure smooth anesthesia (and surgery) by the prevention of adverse physiologic complications. The use of anesthesia modifiers, when the CPT code is not fully descriptive, is required as follows:
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G8 Anesthesia Modifier – used to indicate certain deep, complex, complicated or markedly invasive surgical procedures. This modifier is to be applied to the following anesthesia codes only: 00100, 00300, 00400, 00160, 00532 and 00920.
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G9 Anesthesia Modifier – represents “a history of severe cardiopulmonary disease,” and should be utilized whenever the proceduralist feels the need for MAC due to a history of advanced cardiopulmonary disease. The documentation of this clinical decision making process and the need for additional monitoring must be clearly documented in the medical record.
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Anesthesia codes utilized to indicated the clinical condition of the patient receiving MAC:
 P1 – Healthy individual with minimal anesthesia risk.
 P2 – Mild systemic disease.
 P3 – Severe systemic disease with intermittent threat of morbidity or mortality.
 P4 – Severe systemic illness with ongoing threat of morbidity or mortality.
 P5 – Pre-morbid condition with high risk of demise unless procedural intervention is performed.
Special conditions and/or criteria must be supported by documentation in the medical record.

 Reimbursement for MAC will be the same amount allowed for full general anesthesia services if all the requirements listed under these indications are met. The provision of quality MAC is mandatory and requires the same expertise and the same effort (work) as required in the delivery of a general anesthetic. If the requirements are not fulfilled or the procedures are unnecessary, payment will be denied in full.


For procedures that do not usually require anesthesia services, MAC could be covered when the patient’s condition requires the presence of qualified anesthesia personnel to perform monitored anesthesia in addition to the physician performing the procedure, and is so documented in the patient’s medical record.


The presence of an underlying condition alone, as reported by an ICD-9-CM diagnosis code, may not be sufficient evidence that MAC is necessary. The medical condition must be significant enough to impact on the need to provide MAC such as the patient being on medication or being symptomatic, etc. The presence of a stable, treated condition, of itself, is not necessarily sufficient.


Conditions listed under the “Diagnoses That Support Medical Necessity” section of the LCD, if matched with anesthesia procedures in the “CPT/HCPCS Codes” section of the LCD, could support the need for MAC. Other disease states can also be considered if medical justification is demonstrated.

Note: The QS modifier must be used with the anesthesia service provided if MAC is delivered. This modifier will follow the modifier that indicates who provided the service (AA QS).
The CPT/HCPCS codes listed in the LCD will be subjected to “procedure to diagnosis” editing. If a covered diagnosis found in the LCD is not on the claim, the edit will automatically deny the service as not medically necessary.

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