Modifier GY: Statutorily Excluded Services
The GY modifier tells Medicare a service is never covered by law, such as a routine physical. When to use GY, whether you need an ABN, and GY vs GA vs GZ.
Modifier GY is a HCPCS Level II modifier that tells Medicare the service on the line is excluded by law or isn't a Medicare benefit at all, so the claim line should be denied and the patient is responsible. CMS defines it as "Item or Service Statutorily Excluded or Does Not Meet the Definition of Any Medicare Benefit" (MLN006266). Typical GY services are routine physicals, refractions, hearing aid exams and cosmetic surgery.
Key takeaways
- GY is for services Medicare never covers, not services that might fail medical necessity. Those take GA or GZ.
- No ABN is required for a statutorily excluded service. CMS encourages a voluntary notice, reported with modifier GX.
- A GY line is denied and the patient is liable. Billing it creates a Medicare denial on record that a secondary plan may require.
- Don't use GY on covered preventive services. Medicare pays its own codes for the annual wellness visit and many screenings.
Modifier GY · payment effect
With and without the modifier
99397 without GY · national facility
$0.00
99397-GY · No change to the rate
$0.00
The service is statutorily excluded or isn’t a Medicare benefit. Medicare denies it; the patient can be billed.
When to use the GY modifier
Use GY when the service falls into a category Medicare excludes by statute or that isn't any defined Medicare benefit. The Claims Processing Manual's list of categorical denials (Pub. 100-04, ch. 30, §20.2) includes:
- Routine physicals and most screening tests (§1862(a)(7) of the Social Security Act), such as the preventive medicine visits 99396 and 99397.
- Routine eye care, most eyeglasses and eye exams for them, such as refraction (92015).
- Hearing aids and hearing aid exams.
- Cosmetic surgery (§1862(a)(10)).
- Personal comfort items, orthopedic shoes and foot supports, and most immunizations outside Medicare's covered vaccines.
The fee schedule flags many of these codes with a status of N (non-covered), which you can see on the code page. A status of N plus a statutory category is the clearest case for GY.
When not to use the GY modifier
- Medicare-covered preventive services. The initial preventive physical exam and annual wellness visits (G0438, G0439) are covered benefits with their own codes.
- A service you expect to be covered. Don't add GY to provoke a denial for a covered service; bill it normally.
- Medicare Advantage claims. MA plans set their own non-covered-service rules; follow the plan's instructions.
Do you need an ABN with GY?
No. CMS says ABNs are not required for care that is statutorily excluded or never covered (ch. 30, §50.2.1), but it strongly encourages giving one as a courtesy. Used that way, the patient isn't asked to choose an option or sign. If you give a voluntary notice, report modifier GX along with GY; CMS's ABN booklet says GX can be used with GY or on its own.
How GY affects payment
Medicare doesn't pay a GY line. The claim line is denied as non-covered and the beneficiary is liable, so you may collect your charge from the patient. The limitation-on-liability protections in §1879 of the Act don't apply to statutory exclusions (ch. 30, §20.2), which is why no ABN is needed to shift liability.
GY vs GA, GZ and GX
| Modifier | Situation | ABN | Who pays if denied |
|---|---|---|---|
| GY | Statutorily excluded or not a Medicare benefit | Not required | Patient |
| GX | Voluntary notice given for an excluded service | Voluntary ABN given | Patient |
| GA | Covered service expected to fail medical necessity | Required ABN signed and on file | Patient |
| GZ | Covered service expected to fail medical necessity | No ABN obtained | Provider |
| KX | Therapy above the yearly threshold, still medically necessary | Not applicable | Medicare pays |
CMS descriptors (MLN006266): GA "Waiver of Liability Statement Issued, as Required by Payer Policy"; GX "Notice of Liability Issued, Voluntary Under Payer Policy"; GZ "Item or Service Expected to Be Denied as Not Reasonable and Necessary."
FAQ
What is the GY modifier used for?
To report an item or service Medicare excludes by statute or that doesn't fit any Medicare benefit, such as a routine physical, refraction or cosmetic procedure. The line is denied and the patient is responsible.
What is the difference between modifier GA and GY?
GY is for services Medicare never covers. GA is for services Medicare covers but that you expect to be denied as not reasonable and necessary in this case, and it says a signed ABN is on file. GA requires an ABN; GY doesn't.
Does Medicare pay claims with the GY modifier?
No. A GY line is denied as non-covered. Its purpose is to record the denial and place liability on the patient, not to get paid.
Do I need an ABN for a GY service?
No. An ABN isn't required for statutorily excluded services, though CMS encourages a voluntary notice. If you give one, add modifier GX.
Can GY and GX be billed together?
Yes. CMS's ABN booklet (MLN006266) says to use GY with GX, or separately, when a voluntary notice was given for an excluded service.
Keep reading
- Modifier GA for covered services that may fail medical necessity.
- Modifier KX for therapy above the yearly threshold.
- Modifier GP for physical therapy plan-of-care claims.
- Codes on this page: 99397 99396 92015 G0438 G0439
Sources: CMS MLN006266, Medicare Advance Written Notices of Non-coverage (May 2025); CMS Medicare Claims Processing Manual, Pub. 100-04, ch. 30, §§20.2 and 50.2.1, and ch. 1, §60.4.2. Verified October 6, 2026.
