From the Novitas Medicare website:

Modifiers

Modifiers indicate that a service or procedure performed has been altered by some specific circumstance, but not changed in its definition or code. They are used to add information or change the description of service to improve accuracy or specificity. Modifiers can be alphabetic, numeric or a combination of both, but will always be two digits.

Part B providers: Try our new modifier lookup tool - Find modifier details! Modifier Lookup Tool for JL - Part B only Modifier Lookup Tool for JH - Part B only

Some modifiers cause automated pricing changes, while others are used for information only. When selecting the appropriate modifier to report on your claim, please ensure that it is valid for the date of service billed.

If more than one modifier is needed, list the payment modifiers—those that affect reimbursement directly—first.

Payment modifiers include: 22, 26, 50, 51, 52, 53, 54, 55, 58, 62, 66, 78, 79, 80, 81, 82, AA, AD, AS, TC, QK, QW, and QY.

Informational or statistical modifiers (e.g., any modifier not classified as a payment modifier) should be listed after the payment modifier.

If multiple informational/statistical modifiers apply, you may list them in any order (as long as they are listed after payment modifiers).

Note: It is up to the provider to determine if a modifier applies, and then choose the most appropriate modifier based on medical documentation.

The definition of each modifier can be found within the document linked in the type of modifier column in the chart below.

For modifiers that can be used for more than one topic, please refer to the Additional HCPCS or other CPT for definition.

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Additional HCPCS modifiers 

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Advance beneficiary notice of noncoverage (ABN) modifiers

References

Advanced beneficiary notice of non-coverage

ABN tutorial

Fee for service advance beneficiary notice of noncoverage

Medicare advance beneficiary notices

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Advanced diagnostic imaging appropriate use (AUC) modifiers

As announced in the CY 2024 Physician Fee Schedule (PPS), effective January 1, 2024, CMS is pausing efforts to implement the AUC program for reevaluation and rescinding the AUC regulations at 42 CFR 414.94, reserving this section for future use. CMS has not specified a timeframe within which implementation efforts will recommence. .

Effective January 1, 2024, providers and suppliers should no longer include AUC consultation information on Medicare FFS claims. However, claims containing AUC related codes with dates of service in 2023 and 2024 will continue to process. Codes include G1000 through G1024 and modifiers MA through MH and QQ.

CMS plans to end the above described HCPCS G codes and modifiers, effective December 31, 2024, to assist in claims processing and data analysis.

References

Appropriate use criteria program  MLN Matters article MM13485 - Appropriate Use Criteria for Advanced Diagnostic Imaging: CY 2024 Update

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Anatomical modifiers

Anatomical modifiers include coronary artery, eye lid, finger, side of body, and toe.

Bilateral procedures

Bilateral indicator of 1 must be reported with 1 unit of service and modifier 50. The 50 modifier identifies the service as being performed on both sides of the body. Do not report anatomical modifiers in addition to modifier 50.

If more than one bilateral procedure was performed, report the services on one line, the number of units should be adjusted to reflect the number of bilateral procedures that are performed.

It is recommended that anatomical modifiers only be included when the service is performed unilaterally to show the additional services are not duplicates.

Coronary artery modifiers

Append one of the following modifiers to identify the coronary artery.

Eye lid modifiers

Append one of the following modifiers to identify the upper or lower eye lid.

Finger modifiers

Append one of the following modifiers to identify the digit of the hand.

Side of body modifiers

Use one of the anatomical specific modifiers to designate the area or part of the body which the procedure was performed.

Toe modifiers

Append one of the following modifiers to identify the digit of the foot.

Note: If the anatomical modifiers can’t be described by using one of the above modifiers, reference Proper Use of Modifiers 59 &- X{EPSU}

References

Bilateral indicators Global surgery calculator (JH) (JL) Global surgery & related services Modifier 59 and new modifiers XE, XS, XP, XU Modifier 59 article Ways to avoid an appeal

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Anesthesia modifiers

One of the modifiers listed below must be reported with anesthesia services to indicate who performed the anesthesia service. Modifiers may only be submitted with anesthesia procedure codes (i.e., CPT codes 00100-01999).

Note: CPT codes 01995 or 01996 are not recognized for time units and should not be submitted with time units in the quantity billed field.

Pricing modifiers (AA, QK, AD, QY, QX and QZ) should be placed in the first modifier field. If QS modifier applies, it must be in the second modifier field.

If reporting multiple modifiers, the medical direction modifier should be listed first, followed by any additional modifiers that are needed.

When Billing for more than four concurrent anesthesia procedures, please review this article.

Monitored anesthesia care

Teaching physician

Other modifiers

The modifiers listed below can be reported in the 2nd position under appropriate circumstances in addition to any of the above-referenced modifiers.

Payment indications

Payment for services that meet the definition of ‘personally performed’ is calculated based on the base units (as defined by CMS) and time, in increments of 15-minute units.

Payment for services that meet the definition of ‘medically directed’ or ‘without medical direction’ is calculated based on the base units (as defined by CMS) and time, in increments of 15-minute units. Payment for services that meet the definition of ‘medically directed’ is based on 50 percent of the ‘personally performed’ rate.

References

CMS IOM Pub. 100-04, Medicare claims processing manual, Chapter 12, section 50 How anesthesia reimbursement is calculated LCD, L35049 - Monitored anesthesia care

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Assistant at surgery modifiers

An assistant at surgery is a physician who actively assists the physician in charge of a case in performing a surgical procedure.

Global surgery rules do not apply.

Assistant at surgery modifier fact sheet

• An assistant at surgery is a provider who actively assists the physician in charge of a case in performing a surgical procedure.
• A physician, nurse practitioner, physician assistant or clinical nurse specialist who is authorized to provide such services under state law can serve as an assistant at surgery.
• The “assistant at surgery” provides more than just ancillary services. The operative note should clearly document the assistant surgeon’s role during the operative session.

Facts

• Use the “80” modifier when the assistant at surgery service was provided by a physician.
• Use the “81” This modifier pertains to physician’s services only. Minimal surgical assistance may be identified by adding the modifier 81 to the usual procedure code and describes an assistant surgeon providing minimal assistance to the primary surgeon.
• Use the “82” modifier when a qualified resident surgeon is not available in a teaching facility:
• The unavailability of a qualified resident surgeon is a prerequisite for use of this modifier and the service must have been performed in a teaching facility.
• The circumstance explaining that a resident surgeon was not available must be documented in the medical record. This modifier is not intended for use by non-physician providers. 
• Use the modifier “AS” for assistant at surgery services provided by a physician’s assistant (PA), nurse practitioner (NP), or clinical nurse specialist (CNS). The provider must accept assignment.

Reimbursement

Medicare reimburses services rendered for assistant at surgery by a physician performing as a surgical assistant at 16 percent of the Medicare Physician Fee Schedule Database (MPFSDB) amount.

Services rendered for assistant at surgery by non-physician providers (PA, NP, or CNS) are reimbursed at 85 percent of 16 percent (i.e., 13.6 percent) of the MPFSDB amount.

Assistant at surgery indicators

The Medicare physician fee schedule (MPFS)(JH) (JL) status indicators for assistant at surgery services should be used to determine if the procedure is allowed with the assistance of a second surgeon.

Status definitions

0 = Payment restrictions for assistants at surgery applies to this procedure unless supporting documentation is submitted to establish medical necessity.

Note: Supporting documentation must be submitted at the time of claim submission to established medical necessity and should clearly document the assistant surgeon’s role during the operative session.

1 = Statutory payment restriction for assistants at surgery applies to this procedure. Assistant at surgery may not be paid.

2 = Payment restrictions for assistants at surgery does not apply to this procedure. Assistant at surgery may be paid.

9 = Concept does not apply

Supporting documentation

Documentation is required when modifiers 80, 81, 82 and AS modifiers are reported, and the payment indicator is a “0”.

Documentation must provide a clinical picture of the patient and include:

• The procedures or services performed and support the use of modifiers 80, 81, 82 and AS
• The name of the assistant
• Evidence the assistant surgeon actively participated in the procedure

Clearly document the assistant’s role during the operative session:

• Assistant’s role provides more than ancillary services

Primary surgeon’s signature:

• The assistant is not required to sign the operative report, the primary surgeon’s signature is sufficient
• Modifier 82 requires the circumstance documented in the medical record that a resident surgeon was not available
• Claims with modifiers 80, 81, 82 and AS should be submitted with required documentation following the Unsolicited Paperwork (PWK) process. 
• The PWK is a process allowing providers to submit documentation with an initial claim:
• Detailed information is outlined in Submitting Unsolicited Paperwork (PWK) Segments for Electronic Claims
• Claims will be rejected when reporting modifiers 80, 81, 82 and AS without supporting documentation. Rejected claims will need to be resubmitted using the instructions above for submitting documentation with your initial claim.

References

Assistant at surgery modifiers CMS IOM Pub.100-04, Medicare Claims Processing Manual, Chapter 12, section 20.4.3 CMS IOM, Publication 100-04, Medicare Claims Processing Manual, Chapter 12, section 100.1.7 Global surgery and related services Importance of documentation Assistant at surgery modifiers fact sheet

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End stage renal disease and erythropoiesis stimulating agent modifiers

Claims for erythropoiesis stimulating agent (ESA) for end stage renal disease (ESRD) patients receiving dialysis in renal dialysis facilities reporting a hematocrit level exceeding 39.0% (or hemoglobin exceeding 13.0g/dL) shall also include modifier ED or EE.

For claims reporting hematocrit or hemoglobin levels exceeding monitoring threshold, the payment for the dose shall be reduced by 25% over the preceding month.

You may report that a dose reduction did occur in response to reported elevated hematocrit or hemoglobin level by adding GS modifier on claim. If modifier GS is not reported for hematocrit or hemoglobin levels exceeding the monitoring threshold, the covered dosage will be reduced by 25%.

Injections of ESA for ESRD beneficiaries must include a modifier indicating type of administration.

ESRD billing modifiers

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Global surgery modifiers

The modifiers listed below are used by physicians to indicate a billed service is not part of a global surgical package and is eligible for separate reimbursement. 

Visit our global surgery calculator (JH) (JL) to determine when the global period ends for a surgical procedure.

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Hospice modifiers

Decision trees for hospice billing

The following decision trees should be used to determine when the services of a hospice patient should be covered and when to report the appropriate modifiers.

Billing physician is the attending physician

All other providers

Note: If submitting charges not related to hospice on a UB-04 (or 837I electronic), append condition code 07 (treatment of a non-terminal condition for a hospice patient) along with the GW modifier.

References

CMS IOM Pub. 100-04, Claims Processing Manual, Chapter 11, section 40 Provider specialty: Hospice

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Other CPT Modifiers 

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Podiatry Class Findings Modifiers

Modifiers Q7, Q8, and Q9 are to be used to bill podiatric services.

Class Findings

Class A:

• Non-traumatic amputation of foot or integral skeletal portion thereof

Class B:

• Absent posterior tibial pulse
• Absent dorsalis pedis pulse
• Advanced trophic changes (at least three of the following):
• Decrease or absence of hair growth
• Nail thickening
• Skin discoloration
• Thin and shiny skin texture
• Rubor or redness of skin

Class C:

• Claudication
• Temperature changes (cold feet)
• Edema
• Paresthesia (abnormal spontaneous sensations in feet)
• Burning

For more information on podiatry services and class findings modifiers, please refer to our Routine Foot Care article.

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Quality Reporting Incentive Programs Modifiers

The Merit-based Incentive Payment System (MIPS), formerly Physician Quality Reporting System (PQRS) program encourages individual eligible professionals (EPs) and group practices to report information on the quality of care to Medicare. It’s an opportunity for participating EPs and group practices to assess the quality of care they provide to their patients, helping to ensure that patients get the right care at the right time.

Health Professional Shortage Area and Physician Scarcity Area Modifiers

The Medicare program provides incentive payments to physicians who render services in a Health Professional Shortage Area (HPSA).

Patient Relationship Categories and Codes

The Medicare Access and CHIP Reauthorization act of 2018 requires the development of PRC codes to help the attribution of patients and episodes to one or more physicians or applicable practitioners (clinicians) for purposes of cost measurement.

The Centers for Medicare & Medicaid Services (CMS) has several goals for the voluntary reporting period:

For clinicians to gain familiarity with the categories and experience submitting the codes

To collect data on the use and submission of the codes for analyses to inform the potential future use of these codes in cost measure attribution methodology in the Quality Payment Program

The codes are currently in a voluntary reporting period. Whether and how the codes are reported on claims will not affect Medicare reimbursement. For now, the modifiers have no impact on beneficiaries.

As of January 1, 2018, Medicare Part B Merit-Based Incentive Payment System-eligible clinicians may now report their patient relationships on Medicare claims using the PRC codes. Reporting of these modifiers will be mandatory in the near future and CMS advises clinicians to participate during the voluntary reporting period to ease transition.

Appropriate Use Criteria (AUC)

Effective January 1, 2020 (the start of the AUC program Educational and Operations Testing Period) the modifiers listed in the chart below will be accepted when used to report AUC for Advanced Diagnostic Imaging Services.

References

Health Professional Shortage Area (HPSA) Health Professional Shortage Area / Surgical Incentive Payment Program Merit-based Incentive Payment System (MIPS), formerly Physician Quality Reporting System (PQRS) MLN Matters® Article, MM9342 - 2016 Annual Update for the Health Professional Shortage Area (HPSA) Bonus Payments MLN Matters® Article, MM9781 - 2017 Annual Update for the Health Professional Shortage Area (HPSA) Bonus Payments  MLN Matters® Article, MM11259 - Reporting the HCPCS Level II Modifiers of the Patient Relationship Categories and Codes MLN Matters® Article, MM11268 - Appropriate Use Criteria (AUC) for Advanced Diagnostic Imaging - Educational and Operations Testing Period - Claims Processing Requirements Quality Payment Program

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Surgical modifiers

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Telehealth service modifiers

Telehealth modifiers must be submitted with distant site telehealth services. Generally, interactive audio and video communications must be used to permit real-time communication between distant site physician/practitioner and patient. Patient must be present and participating in telehealth visit.

A list of telehealth services is available on the CMS website.

References

Medicare Learning Network (MLN) Booklet: Telehealth & Remote Monitoring Telehealth.HHS.gov Telehealth FAQ Calendar Year 2026 Telehealth services List of Telehealth Services MM14315 - Medicare Physician Fee Schedule Final Rule Summary: CY 2026 MM13887 - Medicare Physician Fee Schedule Final Rule Summary: CY 2025 Change request 10152, Elimination of the GT Modifier for Telehealth Services CMS IOM Pub. 100-04 Claims Processing Manual, Chapter 12, sections 190 - 190.7 CMS IOM Pub. 100-04 Medicare Claims Processing Manual, Chapter 39, section 30.5 Change Request 10583, Revisions to the Telehealth Billing Requirements for Distant Site Services Change Request 10883, New Modifier for Expanding the Use of Telehealth for Individuals with Stroke  Opioid Treatment Programs Medicare Billing & Payment Provider Specialty: Telehealth services

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Therapy modifiers

Therapy modifiers indicate the discipline of the plan of care.

When reporting modifier CO, the GO modifier should also be submitted to identify the services furnished under an OT plan of care. Note: The CO modifier is not applicable to claims from critical access hospitals.

When reporting modifier CQ, the GP modifier should also be submitted to identify the services furnished under a PT plan of care. Note: The CQ modifier is not applicable to claims from critical access hospitals.

Therapy threshold amount

Note: The KX modifier is used to confirm that services are medically necessary as justified by appropriate documentation in the medical record once the threshold amount has been met. There is one threshold amount for PT and SLP services combined and a separate threshold amount for OT services. Medicare will deny your claims for therapy services above these amounts without the KX modifier.

References

Coding guidelines: Part A outpatient therapy billing at a glance New modifiers to identify occupational therapy (OT) and physical therapy (PT) services provided by a therapy assistant Outpatient rehabilitation Frequently Asked Questions (FAQs)-Part A Physical Therapy FAQs-Part B Provider Specialty: Therapy - Part A Provider Specialty: Rehabilitation services

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There are times when coding and modifier information issued by CMS differs from the American Medical Association regarding the use of modifiers. A clear understanding of Medicare’s rules and regulations is necessary to assign the appropriate modifier.

Examples of when modifiers may be used: 

• Identification of professional or technical only components.
• Repeat services by the same or different provider.
• An increased, reduced, or unusual service.
• Billing for components of a global surgical package.
• Identification of a specific body area.
• To designate a bilateral procedure.
• Identification of service in a clinical trial.