Modifier Description % of Allowed Charge
AA Anesthesia services performed personally by the anesthesiologist 100 percent
AD Medical supervision by a physician; more than four concurrent anesthesia procedures. (Three base units + actual time units allowed) 65 percent
QK Medical direction of two, three, or four concurrent anesthesia procedures involving qualified individuals). 65 percent
QY Medical direction of one CRNA/AA by an anesthesiologist 65 percent
QX CRNA/AA service with medical direction by an anesthesiologist. 35 percent
QZ CRNA service without medical direction by an anesthesiologist. 70 percent
Note: Modifiers are also required for add-on codes 01953, and 01968-01969
Physical Status Modifiers
Physical status modifiers distinguish between various levels of complexity of the anesthesia service provided based on the patient’s condition and are represented by the letter P followed by a single digit. These modifiers are required for Modified Anesthesia Care (MAC).
P1 Normal healthy patient
P2 Patient with mild systemic disease
P3 Patient with severe systemic disease
P4 Patient with severe systemic disease that is a constant threat to life
P5 Moribund patient who is not expected to survive without the operation
P6 Declared brain-dead patient whose organs are being removed for donor purposes
Anesthesiologist Assistants and the QZ Modifier
When providing anesthesia services, anesthesiologist assistants (AAs) must work with anesthesiologist oversight – as specified under the laws of the state where the anesthesiologist and AA practice. Instances in which the required elements to bill a case as medically directed are not met for a case involving an anesthesiologist assistant should be uncommon. If such a circumstance were to happen, it is important to review applicable state law to determine whether the case met the state specific requirements. Upon confirmation that the care was rendered in compliance with such applicable law, it can be reported as a medically supervised case. Via Transmittal 2716, the Centers for Medicare and Medicaid Services (CMS) recently updated the language it uses in its Claims Processing Manual replacing references to CRNAs and to AAs with the term “qualified nonphysician anesthetist” since in most billing circumstances the rules for anesthesiologist assistants and nurse anesthetists are the same; the core distinction is whether the anesthesia professional is a physician or a nonphysician. One exception is that the QZ modifier is specific to nurse anesthetists. This is not a change and is reflective of previous text in
the CMS Claims Processing Manual.
The CMS Claims Processing Manual lists the services an anesthesiologist must perform – and document- in order to report a case as medically directed in Chapter 12, Section 50C: Medical direction occurs if the physician medically directs qualified individuals in two, three, or four concurrent cases and the physician performs the following activities.
• Performs a pre-anesthetic examination and evaluation;
• Prescribes the anesthesia plan;
• Personally participates in the most demanding procedures in the anesthesia plan, including induction and emergence;
• Ensures that any procedures in the anesthesia plan that he or she does not perform are performed by a qualified anesthetist;
• Monitors the course of anesthesia administration at frequent intervals;
• Remains physically present and available for immediate diagnosis and treatment of emergencies; and
• Provides indicated-post-anesthesia care.
The manual further states:
If anesthesiologists are in a group practice, one physician member may provide the pre-anesthesia examination and evaluation while another fulfills the other criteria. Similarly, one physician member of the group may provide post-anesthesia care while another member of the group furnishes the other component parts of the anesthesia service. However, the medical record must indicate that the services were furnished by physicians and identify the physicians who furnished them.
A physician who is concurrently directing the administration of anesthesia to not more than four surgical patients cannot ordinarily be involved in furnishing dditional services to other patients. However, addressing an emergency of short duration in the immediate area, administering an epidural or caudal anesthetic to ease labor pain, or periodic, rather than continuous, monitoring of an obstetrical patient does not substantially diminish the scope of control exercised by the physician in directing the administration of anesthesia to surgical patients. It does not constitute a separate service for the purpose of determining whether the medical direction criteria are met. Further, while directing concurrent anesthesia procedures, a physician may receive patients entering the operating suite for the next surgery, check or discharge patients in the recovery room, or handle scheduling matters without affecting fee schedule payment.
However, if the physician leaves the immediate area of the operating suite for other than short durations or devotes extensive time to an emergency case or is otherwise not available to respond to the immediate needs of the surgical patients, the physician’s services to the surgical patients are supervisory in nature. Carriers may not make payment under the fee schedule.
Medical supervision occurs if the anesthesiologist does not fulfill all the criteria required for medical direction or if the number of concurrent cases exceeds the four case limit. We understand that some payers will allow instances of incomplete medical direction to be reported with one claim from a nurse anesthetist with the QZ modifier. ASA has expressed concerns about potential misuse of the QZ modifier for nurse anesthetists’ services.
– Billing Modifiers
The following modifiers are used when billing for anesthesia services:
• QX – Qualified nonphysician anesthetist with medical direction by a physician.
• QZ – CRNA without medical direction by a physician.
• QS – Monitored anesthesiology care services (can be billed by a qualified nonphysician anesthetist or a physician).
• QY – Medical direction of one qualified nonphysician anesthetist by an anesthesiologist. This modifier is effective for anesthesia services furnished by a qualified nonphysician anesthetist on or after January 1, 1998.
– Qualified Nonphysician Anesthetist and an Anesthesiologist in a Single Anesthesia Procedure
Where a single anesthesia procedure involves both a physician medical direction service and the service of the medically directed qualified nonphysician anesthetist, and the service is furnished on or after January 1, 1998, the payment amount for the service of each is 50 percent of the allowance otherwise recognized had
the service been furnished by the anesthesiologist alone. The modifier to be used for current procedure identification is QX.
Beginning on or after January 1, 1998, where the qualified nonphysician anesthetist and the anesthesiologist are involved in a single anesthesia case, and the physician is performing medical direction, the service is billed in accordance with the following procedures:
• For the single medically directed service, the physician will use the modifier “QY” (MEDICAL DIRECTION OF ONE QUALIFIED NONPHYSICIAN ANESTHETIST BY AN
ANESTHESIOLOGIST). This modifier is effective for claims for dates of service on or after January 1, 1998, and
• For the anesthesia service furnished by the medically directed qualified nonphysician anesthetist, the qualified nonphysician anesthetist will use the current modifier “QX.”
In unusual circumstances when it is medically necessary for both the CRNA and the anesthesiologist to be completely and fully involved during a procedure, full payment for the services of each provider is allowed. The physician would report using the “AA” modifier and the CRNA would use “QZ,” or the modifier for a nonmedically directed case.
Documentation must be submitted by each provider to support payment of the full fee.
• If Part B deductible satisfied, anesthesia fee schedule furnished by qualified nonphysician anesthetist
– Billed with modifier QZ (CRNA without medical direction by an anesthesiologist)
– Reimbursed at 80% of actual charge or applicable locality
– IOM 100-04, Chapter 12, Section 140.3
• Locality anesthesia conversion factor x sum of allowable base/time units
• QZ modifier does not affect payment/allowed amount
– Same as if performed by anesthesiologist
– 100% of the fee schedule