Ob-Gyn Coding Alert

Reader Questions:

Get a Grip on Medicare’s G Modifiers

Published on Fri Oct 08, 2021

Question: Can you explain the difference between the four G modifiers required for use when a Medicare patient signs an advance beneficiary notice (ABN)?

Alabama Subscriber

Answer: When a Medicare patient receives a service from your provider that is normally a covered benefit but one which Medicare will not, or will only partly, cover due to such factors as medical necessity or frequency, your office must provide and ABN to the patient informing them that they are liable to financially cover all or part of the cost of the service. The ABN’s purpose is to notify the patient they may be responsible; it is not a promise of payment from the patient.

When you then submit the claim to Medicare, you need to add more information to give context for the ABN on file, which is usually done by adding modifier GA (Waiver of liability statement issued as required by payer policy, individual case) to the appropriate line on the claim. However, there are three other G modifiers that may come into play depending on the circumstances.

GX (Notice of liability issued, voluntary under payer policy): You would use this when you issue a voluntary ABN for a service Medicare never covers because it is statutorily excluded or is not a Medicare benefit.

GY (Item or service statutorily excluded, does not meet the definition of any Medicare benefit or, for non-Medicare insurers, is not a contract benefit): You would use this modifier to report that Medicare statutorily excludes the item or service, or that the item or service does not meet the definition of any Medicare benefit. (Note: it is NOT necessary to provide the patient with an ABN in these situations as the benefit in question is not a covered benefit).

GZ (Item or service expected to be denied as not reasonable and necessary): You would use this modifier when you expect Medicare to deny payment of the item or service due to a lack of medical necessity, and no ABN was issued. When modifier GZ is used, the patient may not be billed for the service as no ABN was provided.