G1    Most Recent URR of less than 60%
G2    Most Recent URR of 60% to 64.9%
G3    Most Recent URR of 65% to 69.9%
G4    Most Recent URR of 70% to 74.9%
G5    Most Recent URR of 75% or Greater
G6    ESRD Patient for Whom less than 7 Dialysis Sessions have been provided in a Month
GA   Waiver of liability on file
GC   Service Performed, in part, by a Resident under the Direction of a Teaching Physician
GF    non-physician services in a critical access hospital (CAH) electing the All-Inclusive payment method.
GG    Performance and payment of screening & diagnostic mammogram same day/same patient
GH    Diagnostic mammogram converted to a screening mammogram on the same day
GN    Services delivered under an outpatient speech-language pathology
GO    Services delivered under an outpatient occupational therapy
GP     Services delivered under an outpatient physical therapy
GY    Item/Service is statutorily excluded or does not meet the definition of a Medicare benefit
GZ    No signed ABN on file
KX    Services qualifies for therapy capitation exception
LC     Left circumflex coronary artery (Hospitals use with codes 92980–92982, 92995, and 92996)
LD    Left anterior descending coronary artery (Hospitals use with codes 92980–92982, 92995, and 92996)
LT     Left side (used to identify procedures performed on the left side of the body)

Modifier Billing Usage and Guidelines

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.

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


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. 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.

 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. The beneficiary may need Medicare to deny the claim so that it can be submitted to the beneficiary’s secondary insurance.

Supplier Collects Additional Charge for Upgrade – GK/GA Modifiers If a supplier wants to collect the difference from the beneficiary, a properly completed ABN must be obtained. If an ABN is obtained, the supplier bills the HCPCS code for the item that is provided (but that does not meet coverage criteria) with a GA modifier on one claim line and the HCPCS code for the item that meets coverage criteria with a GK modifier on the next claim line. (Note: The codes must be billed in this specific order on the claim.) In this situation, the claim line with the GA modifier will be denied as not medically necessary with a “patient responsibility” (PR) message and the claim line with the GK modifier will continue through the usual claims processing.