Modifiers Guide - Healthcare

Modifiers GA GX GY and GZ

Modifiers GA GX GY and GZ are HCPCS Level II most commonly used Medicare Advance Beneficiary Notice – ABN modifiers.

Let us know about the description of above ABN modifiers and instructions to use with a CPT code, but before moving to that part first let us learn the term ABN –Advance Beneficiary Notice.

ABN –Advance Beneficiary Notice:

ABN is also known as Waiver of Liability, signed by Medicare patients. In other way we can say a notice the hospital or doctor gives the patient before the treatment, telling the patient that Medicare may not pay for some treatment or services.  This ABN document is signed by the patient, stating that, in case of Medicare is not going to pay, or not covering the payment, the patient himself is liable for the payment.

Important guidelines:

  • ABN modifiers are prohibited for Medicare advantage enrollees. As per CMS, dated on May 05, 2014 released that Advance Beneficiary notice modifiers i.e. GA, GX, GY or GZ to be used only for Medicare beneficiaries and not to be used for members of Medicare advantage plans.
  • If provider appends GA, GY or GZ Modifiers on the same claim line as a combination, then it is invalid and claim will be denied. So don’t place any combination of GA, GY or GZ modifiers on the same claim line.


GA Modifier

Append GA modifier for the item or service when a carrier wants the physician to present an ABN. This GA modifier is to notify Medicare from provider that ABN is on file, and provider anticipates Medicare probably or certainly will not to cover those item or service. So by this provider indicates that patient has signed ABN form by appending GA modifier to CPT and patient will be responsible for the charges billed, if those items or service not covered by Medicare.


GA modifier should be append to a CPT, for which the provider had a patient sign an ABN form because there is a possibility the service may be denied because the patient’s diagnosis might not medically necessary. By this provider ensure upon Medicare denial, member will be liable to pay those services.

Important Note:

  • GA Modifier cannot be reported with liability related modifiers GZ, EY, GX, KB, QL, TX or TS.
  • GA Modifier cannot be used with KX modifier while billing the DME claims.


GX Modifier

GA Modifier and GX Modifier were formed to distinguish between mandatory and voluntary ABN’s respectively.

Append GX Modifier to a CPT when a voluntary Advance Beneficiary Notice is issued to a beneficiary for any services not covered by Medicare.

Important Note:

  • GX Modifier may be reported with GY Modifier and TS Modifier, but not to be reported with EY, GA, GL, GZ, KB, QL or TQ Modifiers.


GY Modifier

Append GY Modifier to notify Medicare that you know this CPT is statutorily excluded and will not be covered.

Some of the services such as cosmetic surgery, dental care, acupuncture are statutorily excluded by Medicare. In that case we report those services with GY Modifier to indicate those services are excluded.

For Example:

CPT 15775 and 15776 performed for cosmetic reason will be denied as non-covered. Medicare does not cover cosmetic surgery codes that are performed to reshape or improve the beneficiary appearance.

Provider knows this before giving service to patient that cosmetic service will not be covered by Medicare. When billing this cosmetic code to Medicare, provider appends the GY modifier to indicate that this service is statutorily excluded and will be denied. Once Medicare denies this service, patient is responsible and provider can reimburse money from the patient for those services.

Important Note:

  • GY Modifier should not be reported with add on codes.


GZ Modifier

If ABN not obtained or unsigned then CPT should be billed with GZ modifier, when you know those CPT will be denied as not medically necessity by Medicare.