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.
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.
Medicare Part B Anesthesia Modifiers
Medicare’s coverage of anesthesia services range from the least intensive to the most intensive services and include:
1. Local or topical anesthesia – the least intense;
2. Moderate (conscious sedation);
3. Regional anesthesia; and
4. General anesthesia – monitored anesthesia care (MAC).
Medicare covers MAC when provided for services considered reasonable and necessary. Services involving the administration of anesthesia are reported by the use of a 5-digit anesthesia procedure code (00100 – 01999) along with applicable modifiers.
A surgeon or physician cannot bill for anesthesia at the same time he/she is performing surgery. The Centers for Medicare and Medicaid Services (CMS) recently published Medicare Learning Network (MLN) article MM5618 “Anesthesia Services Furnished by the Same Physician Providing the Medical and Surgical Service – Revised.” This article can be found in Medicare B News Issue 240, October 2, 2007 and covers conscious sedation codes 99143, 99144, 99145, 99148, 99149 and 99150. Providers who bill these codes are encouraged to review this article thoroughly.
Medically directed anesthesia services should be billed using the appropriate modifiers listed below.
•AA: Anesthesia services personally performed by an anesthesiologist.
This modifier allows full fee schedule reimbursement.
• AD: Medical supervision by a anesthesiologist: more than 4 concurrent anesthesia procedures
Per the Internet Only Manual (IOM) Publication 100-04; Chapter 12, Section 50.D: “Carriers may allow only three base units per procedure when the anesthesiologist is involved in furnishing more than four procedures concurrently or is performing other services while directing the concurrent procedures. An additional time unit may be recognized if the anesthesiologist can document that he or she was present at induction.”
• QK: Medical direction of 2, 3 or 4 concurrent anesthesia procedures involving qualified individuals.
This modifier limits payment to 50% of the amount that would have been allowed if personally performed by a anesthesiologist or non-supervised CRNA.
• QX: CRNA service with medical direction by a anesthesiologist.
This modifier limits payment to 50% of the amount that would have been allowed if personally performed by an anesthesiologist or non-supervised CRNA.
• QY: Anesthesiologist medically directs one CRNA.
This modifier limits payment to anesthesiologist and CRNA to 50% of the amount that would have been allowed if personally performed by anesthesiologist.
• QZ: CRNA service without medical direction by a anesthesiologist.
This modifier has no affect on payment and the allowed amount is what would have been allowed if personally performed by an anesthesiologist.
As a reminder, the anesthesia modifiers above are pricing modifiers and must be listed in first position to insure correct reimbursement.
The modifiers below: QS, G8 and G9 modifiers are informational only and do not affect payment. Informational modifiers must be used in the second modifier position, in conjunction with a pricing anesthesia modifier in the first modifier position.
• QS: Monitored anesthesia care (MAC)
• G8: MAC for deep complex complicated or markedly invasive surgical procedures and may be used in lieu of modifier QS.
• G9: MAC for a patient who has a history of severe cardiopulmonary condition and may be used in lieu of modifier QS.
In Medicare B News Issue 246 June 24, 2008 NAS published “Anesthesia Base Rate Pricing.” This article is a good resource to help providers determine correct base and time units as well as the reimbursement formula.
Applies to the states of: AK, AZ, MT, ND, OR, SD, UT, WA & WY.
Incorrect Billing Modifiers
Modifier Do Not file on the same claim line with:
AA – Anesthesiologists AD, QY, QK, QX, or QZ
QY – Anesthesiologists AA, AD, QK, QX, or QZ
QK – Anesthesiologists AA, AD, QY, QX, or QZ
AD – Anesthesiologists AA, QY, QK, QX, or QZ
QX – CRNAs AA, AD, QY, QK, or QZ
QZ – CRNAs AA, AD, QY, QK, or QX
QX Qualified non-physician anesthetist with medical direction by physician. 80 percent of the payment made for the QK or QY claim effective 10/1/2014 date of service
Anesthesia claims are paid based on the following:
Time units + Base unit x Anesthesia Conversion factor. Neighborhood uses the Centers for Medicare and Medicaid Services (CMS) base unit values.
* Anesthesia Personally Performed by Anesthesiologist or CRNA (AA or QZ Modifier) (Total Time Units + Base Unit) x Anesthesia Conversion Factor x Modifier Adjustment = Allowance
* Anesthesia Performed under Medical Direction (QK, QX and QY modifiers) [(Total Time Units + Base Unit) x Anesthesia Conversion Factor] x Modifier Adjustment = Allowance for each provider
Reimbursement for Anesthesia Administered by a CRNA
• CRNA services billed with modifier QY, reporting medically directed services, are reimbursed at 50 percent.
• CRNA services billed with modifier QZ, reporting services without medical direction, are reimbursed at 100 percent
• When a CRNA assumes the role of second anesthesiologist, a medical direction situation does not exist and the anesthesiologist should bill with modifier AA and the CRNA should bill with modifier QZ. The first anesthesiologist will be reimbursed for the full basic value plus time and modifying units at 100 percent. The CRNA will be reimbursed for a basic value of five units plus time and modifying units at 100 percent.
QZ CRNA Service without Medical Direction by a Physician: Regional or general anesthesia provided by the CRNA without medical direction by a physician may be reported by adding modifier QZ. Claims submitted with modifier QZ are reimbursed at 100 percent.
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.
In anesthesia every anesthesia procedure billed to Medicare must include one of the following anesthesia HCPCS modifiers:
• AA: Anesthesia services performed personally by anesthesiologist or when an anesthetist assists a physician in the care of a single patient.
• QY: Medical direction of one Qualifi ed Nonphysician
• QK: Medical direction of two, three or four concurrent anesthesia procedures involving qualifi ed individuals.
• AD: Medical supervision by a physician: more than four concurrent anesthesia procedures.
• QX: Qualified Nonphysician Anesthetist service: with medical direction by a physician.
• QZ: Qualified Nonphysician Anesthetist service: without medical direction by a physician. Note: For examples of correct and incorrect usage of each modifier, refer to our “Modifier Lookup Tool” on the Palmetto GBA website under the “Self-Service Tools” on the home page.
In addition to the above modifiers, there are others modifiers that may be used to identify specific situations in addition to the above required modifiers. Additional HCPCS Modifiers Anesthesiologist
Note: Do not use these HCPCS modifiers if the provider of service is a Qualifi ed Nonphysician Anesthetist or AA
• AA : Anesthesia service personally performed by the anesthesiologist.
• QY: Medical direction of one Qualified Nonphysician Anesthetist by an anesthesiologist.
• QK: Medical direction of two, three or four concurrent anesthesia procedures.
• AD: Supervision, more than four procedures. Qualifi ed Nonphysician Anesthetist
Note: Do not use these HCPCS modifiers if the provider of service is an Anesthesiologist
• QX: Anesthesia, Qualified Nonphysician Anesthetist medically directed.
• QZ: Anesthesia, Qualified Nonphysician Anesthetist not medically directed. Monitored Anesthesia Care (MAC)
• QS: Monitored Anesthesia Care services (can billed by a Qualified Nonphysician Anesthetist, AA or physician).
Anesthesia Modifiers Description Adjustment Rate
Modifier AA – Administered by anesthesiologist – 100% of Fee Schedule Allowance/Contracted Rate
Modifier AD – Medical supervision more then four concurrent anesthesia procedures – 50% of Fee Schedule Allowance/Contracted Rate
Modifier QK – Medical direction of two three or four concurrent anesthesia procedures involving qualified individuals – 50% of Fee Schedule Allowance/Contracted Rate
Modifier QS – Monitored anesthesia service – 100% of Fee Schedule Allowance/Contracted Rate
Modifier QX – Administered by CRNA with medical direction – 50% of Fee Schedule Allowance/Contracted Rate
Modifier QY – Medical direction of CRNA by anesthesiologist – 50% of Fee Schedule Allowance/Contracted Rate
Modifier QZ – Administered by CRNA without medical direction – 100% of Fee Schedule Allowance/Contracted Rate
Modifier QS: Monitored Anesthesia
Modifier QS denotes monitored anesthesia services. “Monitored anesthesia care” (MAC) involves the intraoperative monitoring of the patient’s vital physiological signs, in anticipation of the need for administration of general anesthesia or of the development of adverse physiological patient reaction to surgery. It also includes the performance of a pre-anesthetic examination and evaluation, prescription of the anesthesia care required, administration of any necessary oral and parenteral medications, and provisions of indicated post-operative anesthesia care. Monitored anesthesia services can be rendered only by anesthesiologists and CRNAs.
Monitored anesthesia time involves the continuous actual physical presence of the anesthesiologist or the CRNA. The time starts when the anesthesiologist or CRNA begins to prepare the patient for anesthesia care in the operating room or equivalent area. Time ends when the anesthesiologist or CRNA is no longer in personal physical attendance (i.e., when the patient may be safely placed under post-operative supervision).
Injection of an anesthetic substance as the form of anesthesia for a procedure is billed with the appropriate procedure code (62274-62279, 67500) without modifier YA or QS appended. This type of anesthesia is not reimbursed by time, therefore, units should represent the number of services rendered. These injection procedures (most commonly epidurals) are not allowed on the same day as general anesthesia (modifier YA) or monitored anesthesia (modifier QS) unless the injection or insertion of the catheter is subsequent to the procedure and performed only for management of post-operative pain. In this situation, the appropriate procedure code should be billed with modifier 59 to designate the service as unrelated to the surgical procedure. (Refer to Regional Anesthesia in Anesthesia Services.)
• Monitored anesthesia services billed by the anesthesiologist or CRNA are billed with the same primary procedure code as billed by the operating physician.
• When billing time, one minute equals one unit.
• Unusual forms of monitoring such as intra-arterial, central venous, and Swan Ganz are not included in anesthesia services and can be billed separately. Modifier 59 does not have to be appended to the procedure code in order to be reimbursed separately.
• Modifier YA and QS is an invalid modifier combination and cannot be billed on the same claim detail. If monitored anesthesia results in general anesthesia, only general anesthesia is billed with combined time units.
• Providers rendering monitored anesthesia services are required to maintain documentation on file for a period of five years. This information must include documentation of the pre-anesthetic examination and evaluation, documentation of the monitoring of the patients’ vital physiological signs and a post-operative anesthesia note.
• The only anesthesia modifiers that Medicaid will recognize are QS and YA. HCPCS modifiers AA, AD, AE, QJ, QO, QQ, QX, and QZ will not be recognized and if billed, will result in the claim being denied.
• There will be no separate reimbursement for the operating physician if he performs an anesthesia related service such as an injection of a local or regional block.