Definitions of the GA, GY, GX and GZ Modifiers

1. Definitions of the GA, GY, and GZ Modifiers

The modifiers are defined below:

GA – Waiver of liability statement on file.

GY – Item or service statutorily excluded or does not meet the definition of any Medicare benefit.

GZ – Item or service expected to be denied as not reasonable and necessary.


2. Use of the GA, GY, and GZ Modifiers for Services Billed to Local Carriers

The GY modifier must be used when physicians, practitioners, or suppliers want to indicate that the item or service is statutorily non-covered or is not a Medicare benefit.

The GZ modifier must be used when physicians, practitioners, or suppliers want to indicate that they expect that Medicare will deny an item or service as not reasonable and necessary and they have not had an Advance Beneficiary Notification (ABN) signed by the beneficiary.

The GA modifier must be used when physicians, practitioners, or suppliers want to indicate that they expect that Medicare will deny a service as not reasonable and necessary and they do have on file an ABN signed by the beneficiary. (See http://www.cms.hhs.gov/medlearn/refabn.asp for additional information on use of the GA modifier and ABNs.)

The GY and GZ modifiers should be used with the specific, appropriate HCPCS code when one is available. In cases where there is no specific procedure code to describe services, a “not otherwise classified code” (NOC) must be used with either the GY or GZ modifier.

3. Use of the GA, GY, and GZ Modifiers for Items and Supplies Billed to DMERCs

The GY modifier must be used when suppliers want to indicate that the item or supply is statutorily noncovered or is not a Medicare benefit.

The GZ modifier must be used when suppliers want to indicate that they expect that Medicare will deny an item or supply as not reasonable and necessary and they have not had an Advance Beneficiary Notification (ABN) signed by the beneficiary.

The GA modifier must be used when suppliers want to indicate that they expect that Medicare will deny an item or supply as not reasonable and necessary and they do have on file an ABN signed by the beneficiary. The GY and GZ modifiers should be used with the specific, appropriate HCPCS code when one is available. In cases where there is no specific procedure code to describe items or supplies, an NOC must be used with either the GY or GZ modifiers.

4. Use of the A9270

Effective January 1, 2002, the A9270, Noncovered item or service, under no circumstances will be accepted for services or items billed to local carriers. However, in cases where there is no specific procedure code for an item or supply and no appropriate NOC code available, the A9270 must continue to be used by suppliers to bill DMERCs for statutorily non-covered items and items that do not meet the definition of a Medicare benefit.


5. Claims Processing Instructions

At carrier and DMERC discretion, claims submitted using the GY modifier may be auto-denied. If the GZ and GA modifiers are submitted for the same item or service, treat the item or service as having an invalid modifier and therefore unprocessable.


F. GZ Modifier

Effective for dates of service on and after July 1, 2011, contractors shall automatically deny claim line(s) items submitted with a GZ modifier. Contractors shall not perform complex medical review on claim line(s) items submitted with a GZ modifier. All MACs shall make all language published in educational outreach materials, articles, and on their Web sites, consistent to state all claim line(s) items submitted with a GZ modifier shall be denied automatically and will not be subject to complex medical review. When claim line(s) items submitted with the Modifier GZ are denied, contractors shall use the following codes: Group Code CO (Provider/Supplier liable) and CARC 50 defined “These services are non-covered services because this is not deemed a ‘medical necessity’ by the payer.

The modifiers are defined below:

GA – Waiver of liability statement on file.


 GY – Item or service statutorily excluded or does not meet the definition of any Medicare benefit.


GZ – Item or service expected to be denied as not reasonable and necessary.

GZ Modifier

Effective for dates of service on and after July 1, 2011, A/B MACs (B) shall automatically deny claim line(s) items submitted with a GZ modifier. A/B MACs (B) shall not perform complex medical review on claim line(s) items submitted with a GZ modifier. All MACs shall make all language published in educational outreach materials, articles, and on their Web sites, consistent to state all claim line(s) items submitted with a GZ modifier shall be denied automatically and will not be subject to complex medical review. When claim line(s) items submitted with the Modifier GZ are denied, A/B MACs (B) shall use the following codes: Group Code CO (Provider/Supplier liable) and CARC 50 defined “These services are non-covered services because this is not deemed a ‘medical necessity’ by the payer.

2. Use of the GA, GY, and GZ Modifiers for Services Billed to A/B MACs (B)

The GY modifier must be used when physicians, practitioners, or suppliers want to indicate that the item or service is statutorily non-covered or is not a Medicare benefit.

The GZ modifier must be used when physicians, practitioners, or suppliers want to indicate that they expect that Medicare will deny an item or service as not reasonable and necessary and they have not had an Advance Beneficiary Notification (ABN) signed by the beneficiary.

The GA modifier must be used when physicians, practitioners, or suppliers want to indicate that they expect that Medicare will deny a service as not reasonable and necessary and they do have on file an ABN signed by the beneficiary. (See https://www.cms.gov/Outreach-and-Education/Medicare-Learning-Network-MLN/MLNProducts/downloads/abn_booklet_icn006266.pdf for additional information on use of the GA modifier and ABNs.)

The GY and GZ modifiers should be used with the specific, appropriate HCPCS code when one is available. In cases where there is no specific procedure code to describe services, a “not otherwise classified code” (NOC) must be used with either the GY or GZ modifier.

GA and GZ Modifiers

Providers and suppliers use GA and GZ modifiers to bill for certain services or items that they expect to be denied as not reasonable and necessary.3 They may use these modifiers when they are uncertain about whether a claim should be paid. For example, a provider may not know whether a beneficiary already had a particular laboratory test that Medicare covers only once a year 4 or a supplier may suspect that the beneficiary already has the item it is providing.5  Providers and suppliers may also use these modifiers when they are certain that the claim should not be paid. For example, a provider may know that Medicare does not pay for a particular test for a beneficiary with a given condition, but because the beneficiary requests it, the provider submits the claim to Medicare for a decision.6  The beneficiary may need Medicare to deny the claim so that it can be submitted to the beneficiary’s secondary insurance.

GZ Modifiers: Beginning in January 2002, Medicare required providers and suppliers to use the GZ modifier for claims they expect to be denied as not reasonable and necessary for which they do not have an ABN on file.8  In these cases, if Medicare denies the claim as not reasonable and necessary, the beneficiary cannot be held liable for the cost of the service or item. Table 1 provides the definitions of GA and GZ modifiers for Part B claims.

Definitions of GA and GZ Modifiers for Part B Claims

Modifier         Definition

GA Service or item is not considered reasonable and necessary; ABN is on file

GZ Service or item is not considered reasonable and necessary; ABN is not on file

Medicare Part B Claims Processing

CMS contracts with Medicare Administrative Contractors (MAC) to process and pay Part B claims.12 These contractors also apply claims processing “edits”—i.e., system checks—to prevent improper payments; conduct medical reviews and data analyses of claims; and conduct outreach and education to providers. Edits flag a claim for automatic denial or for contractor review to ensure that the claim is appropriate.

CMS provides contractors with various instructions about how to process claims with G modifiers. CMS required contractors to automatically deny claims with GZ modifiers for services or items that were provided on or after July 1, 2011. 13 Currently, CMS does not have any specific instructions for claims with GA modifiers, except for those submitted with both a GA and GZ modifier; CMS instructs contractors to treat such  claims as unprocessable.14 For claims with GY modifiers, CMS allows contractors to deny these claims at their discretion. Finally, CMS has not issued instructions for processing Part B claims with GX modifiers.

Processing Instructions for Part B Claims With G Modifiers


Modifier             Processing Instructions

GA   Claims with both a GA and a GZ modifier for the same service or item should be treated as unprocessable.

GZ Effective July 1, 2011, GZ claims must be automatically denied.

GY     Effective January 2002, claims with GY modifiers may be automatically denied at the discretion of the MACs.

GX No instructions

3. Use of the GA, GY, and GZ Modifiers for Items and Supplies Billed to DME MACs

The GY modifier must be used when suppliers want to indicate that the item or supply is statutorily non-covered or is not a Medicare benefit.

The GZ modifier must be used when suppliers want to indicate that they expect that Medicare will deny an item or supply as not reasonable and necessary and they have not had an Advance Beneficiary Notification (ABN) signed by the beneficiary.

The GA modifier must be used when suppliers want to indicate that they expect that Medicare will deny an item or supply as not reasonable and necessary and they do have on file an ABN signed by the beneficiary.

The GY and GZ modifiers should be used with the specific, appropriate HCPCS code when one is available. In cases where there is no specific procedure code to describe items or supplies, an NOC must be used with either the GY or GZ modifiers.

A GY modifier is used by providers when billing to indicate that an item or service is statutorily excluded and is not covered by Medicare. Examples of statutorily excluded services include hearing aids and home infusion therapy.

When these types of claims are rejected, we also will remind the provider to allow 30 days for the crossover process to occur or instruct the provider to submit the claim with only GY modifier service lines indicating the claim only contains statutorily excluded services.

Medicare statutorily excluded services – just file once to your local Blue Cross Blue Shield plan

There are certain types of services that Medicare never or seldom covers, but a secondary payer such as Anthem may cover all or a portion of those services. These are statutorily excluded services. For services that Medicare does not allow, such as home infusion, providers need only file statutorily excluded services directly to their local plan using the GY modifier and will no longer have to submit to Medicare for consideration. These services must be billed with only statutorily excluded services on the claim and will not be accepted with some lines containing the GY modifier and some lines without.

For claims submitted directly to Medicare with a crossover arrangement where Medicare makes no allowance, providers can expect the member’s benefit plan to reject the claim advising the provider to submit to their local plan when the services rendered are considered eligible for benefit. These claims should be resubmitted as a fresh claim to a provider’s local plan with the Explanation of Medicare Benefits (EOMB) to take advantage of provider contracts. Since the services are not statutorily excluded as defined by CMS, no GY modifier is required. However, the submission of the Medicare EOMB is required. . This will help ensure the claims process consistent with the providers contractual agreement..

Providers who render statutorily excluded services should indicate these services by using GY modifier at the service line level of the claim. Providers will be required to submit only statutorily excluded service lines on a claim (cannot combine with other services like Medicare exhaust services or other Medicare covered services)

? The provider’s local plan will not require Medicare EOMB for statutorily excluded services submitted with a GY Modifier.

If providers submit combined line claims (some lines with GY, some without) to their local plan, the provider’s local plan will deny the claims, instructing provider to split the claim and resubmit

Original Medicare — The GY modifier should be used when service is being rendered to a Medicare primary member for statutorily excluded service and the member has Blue secondary coverage, such as an Anthem Medicare Supplement plan. The value in the SBR01 field should not be “P” to denote primary.

Medicare Advantage — Please ensure SBR01 denotes “P” for primary payer within the 837 electronic claim file. This helps ensure accurate processing on claims submitted with a GY modifier.

The GY modifier should not

• Commercial claims be used when submitting:

• Federal Employee Program claims

• In-patient institutional claims. Please use the appropriate condition code to denote statutorily excluded services.

Medicare usage guidelines

You should be aware of some details in the use of these modifiers.

• -GA Modifier:

• Medicare systems will automatically deny lines submitted with the -GA modifier and covered charges on institutional claims;

• Medicare systems will assign beneficiary liability to claims automatically denied when the –GA modifier is present; and

• Medicare will use claim adjustment reason code 50 (These are noncovered services because this is not deemed a ‘medical necessity’ by the payer.) when denying lines due to the presence of the –GA modifier.

• -GX Modifier

• Medicare systems will recognize and allow the –GX modifier on claims, but will return your claim if the –GX modifier is used on any line reporting covered charges;

• Medicare systems will allow the –GX modifier to be reported on the same line as the following modifiers that indicator beneficiary liability: -GY (Item or service statutorily excluded or does not meet the definition of any Medicare benefit), -TS (Follow-up service);

• Medicare systems will return your claim if the –GX modifier is reported on the same line as any of the following liability-related modifiers: -EY (no doctor’s order on file), -GA, -GL (medically unnecessary upgrade provided instead of non-upgraded item, no charge, no ABN), -GZ (item or service expected to be denied as not reasonable and necessary), -KB (Beneficiary requested upgrade for ABN, more than four modifiers identified on claim), -QL (Patient pronounced dead after ambulance is called), -TQ (basic life support transport by a volunteer ambulance provider);

• Medicare systems will automatically deny lines (using claim adjustment reason code 50) submitted with the -GX modifier and non-covered charges, and will assign beneficiary liability to claims automatically denied when the –GX modifier is present.

Final Note: Other than the policy and processing changes described in CR 6563, all other policies and processes regarding non-covered charges and liability continue as stated in the Medicare Claims Processing Manual, Chapter 1 (General Billing Requirements), Section 60 (Provider Billing of Noncovered Charges) and in the requirements defined in previous change requests.