HCPCS Modifier GY

What modifier GY means

Modifier GY indicates a service is statutorily excluded from Medicare or does not meet the definition of any Medicare benefit (e.g., routine physicals, hearing aids, most cosmetic procedures). Appending GY produces an automatic, expected denial, which is what you need in order to bill the patient or forward the claim to a secondary payer. Because the service is statutorily excluded, an ABN is not required (a voluntary notice may still be issued — see GX).

When to use it

Bill a service Medicare never covers and you need a formal Medicare denial to collect from the patient or a secondary plan.

Documentation checklist

The record should support every item below before you append modifier GY.

• The statutory basis for exclusion (the service is not a Medicare benefit)
• Patient acknowledgment of financial responsibility (or a voluntary ABN, paired with GX)
• Secondary payer / patient billing information

Do NOT use modifier GY when

• The service may actually be covered but medical necessity is in doubt — use GA (ABN obtained) or GZ (no ABN)
• Coverage is expected
• The denial you need is a medical-necessity denial rather than a statutory exclusion

Common denial reasons

• By design the line denies as non-covered (e.g., PR-204 / CO-96) so liability moves to the patient
• Used on a service that is in fact covered, producing an incorrect patient-liability denial

How to appeal a modifier GY denial

A GY denial is usually the intended outcome, so the path is collection from the patient/secondary rather than appeal. If Medicare was billed in error for a covered service, resubmit without GY (or with the correct GA/GZ) and the supporting medical-necessity documentation.

Payer notes

GY shifts liability to the patient for a statutorily excluded service; no ABN is legally required, though a voluntary one (with GX) is good practice. Commercial recognition of GY varies — many plans handle non-covered services through their own remittance codes instead.

Related & commonly confused modifiers

Where modifier GY is used

• Routine/screening exams not covered by statute
• Non-covered HCPCS supplies and DME
• Cosmetic procedures