Modifier GY

GY marks a line Medicare will never pay, not because this patient’s case failed a medical necessity test but because the item or service sits outside the program. CMS’s ABN booklet says to report it when the law excludes the item or service, or when it is not part of any benefit Medicare defines. CMS’s list of exclusions includes routine or annual physical checkups, exams done with no specific sign, symptom or complaint, eyeglasses and the eye exams to prescribe them, and hearing aids and hearing exams.

No ABN is required before these services. CMS recommends a voluntary notice as a courtesy so the patient knows the cost is theirs, and when one is given, the line can carry GX alongside GY. Giving the notice voluntarily does not change who pays. For institutional claims, Medicare’s processing manual treats GY lines as noncovered: they are submitted that way and denied, with the beneficiary liable.

The error to avoid is using GY when the real issue is medical necessity. A service Medicare normally covers but may deny for this patient, such as a test billed more often than its frequency limit, is not excluded; it needs a valid ABN and GA, or GZ when no ABN was given. Putting GY on a covered service to force a denial misstates the claim. Check the exclusion list first, then choose the modifier that matches the reason Medicare will not pay.