HCPCS Modifier GZ

Item or service expected to be denied as not reasonable and necessary and an Advance Beneficiary Notice (ABN) has not been signed by the beneficiary.

Guidelines and Instructions

  • Submit HCPCS modifier GZ when there is no valid ABN on file for a service that you expect Medicare will deny as not reasonable and necessary
  • Effective July 1, 2011, claim lines containing HCPCS modifier GZ will be automatically denied and will not be subject to complex medical review
  • HCPCS modifier GZ may not be submitted with services that are statutorily excluded. Refer to HCPCS modifier GY for these services.

ABN Background

  • Both Medicare beneficiaries and providers have certain rights and protections related to financial liability under the Fee-For-Service (FFS) Medicare and the Medicare Advantage (MA) Programs. These financial liability and appeal rights and protections are communicated to beneficiaries through notices given by providers.
  • All providers are required to use the CMS ABN form, available on the CMS website
  • The ABN form must be presented to the patient before the service or procedure is initiated. Maintain a copy of the form in the patient’s medical record.


  • CMS ABN (Form CMS-R-131) and instructions for completion

Last Updated: 07/16/2020