ABN Modifiers
Modifier GA should be used when physicians, practitioners, or suppliers want to indicate that they expect that Medicare will deny an item or service as reasonable and necessary and they have on file an Advance Beneficiary Notification (ABN) signed by the beneficiary. Modifier GY should 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.
Modifier GZ should 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 Notice (ABN) signed by the beneficiary.