When the previous instructions have been followed and a valid ABN on file, the following modifiers should be used to notify Medicare:
- GA Use to indicate that an ABN was given as required by payer policy. A copy of the ABN does not have to be submitted but must be made available upon request.
- GX Used to indicate that an ABN was given voluntarily under payer policy (UB-04) claims.
- GZ Use when an item or service is expected to be denied as not reasonable and necessary and an ABN has not been signed. Effective July 1, 2011, all claim line items submitted with a GZ modifier will be denied automatically and will not be subject to complex medical review.