Modifier GY is a HCPCS Level II modifier used to indicate that an item or service is statutorily excluded from Medicare coverage or does not meet the definition of a Medicare benefit. Unlike Modifier GZ, which applies to services expected to be denied because they are not reasonable and necessary, Modifier GY is used when Medicare does not cover the service at all under the law, regardless of medical necessity.

Modifier GY is primarily reported on Medicare Part B claims and helps Medicare process claims for non-covered services appropriately. It also assists providers in establishing the correct financial responsibility when services are outside Medicare’s benefit categories.

Understanding Modifier GY is essential for accurate claim submission, compliance with Medicare regulations, and proper patient financial counseling.

Modifier

Modifier Name

Item or Service Statutorily Excluded or Does Not Meet the Definition of Any Medicare Benefit

Plain English Explanation

Modifier GY tells Medicare:

“This item or service is not covered by Medicare because it is excluded by law or is not considered a Medicare benefit.”

Purpose of Modifier GY

Modifier GY is used to:

Identify services that Medicare does not cover by statute.
Distinguish non-covered services from medically unnecessary services.
Support proper Medicare claim processing.
Establish correct patient financial responsibility when appropriate.
Differentiate statutory exclusions from medical necessity denials.

Understanding Modifier GY

Medicare covers only services that are authorized under federal law and meet applicable coverage requirements.

Modifier GY is used when:

The service is never covered by Medicare because it is excluded by statute, or
The service does not meet the legal definition of a Medicare benefit.

Examples include certain routine services, personal convenience items, and other services that Medicare excludes from coverage by law.

Modifier GY is not appropriate simply because documentation is inadequate or because the service lacks medical necessity. Those situations involve different modifiers, such as GZ or GA, depending on whether a valid Advance Beneficiary Notice (ABN) was obtained.

When to Use Modifier GY

Modifier GY is appropriate when:

The item or service is statutorily excluded from Medicare coverage.
The service is not included within any Medicare benefit category.
Medicare law specifically excludes the service.
The provider submits the claim to obtain an official Medicare denial.

Common Examples

✔ Routine physical examinations that are not covered under a Medicare benefit category (unless specifically covered by statute, such as the Initial Preventive Physical Examination or Annual Wellness Visit).

✔ Cosmetic procedures performed solely for appearance and not covered under Medicare.

✔ Personal comfort or convenience items that are excluded from Medicare benefits.

✔ Other services specifically excluded by the Social Security Act or Medicare regulations.

When NOT to Use Modifier GY

Do not use Modifier GY when:

The service is covered by Medicare but lacks medical necessity (Modifier GA or GZ may apply).
A valid Advance Beneficiary Notice (ABN) is obtained for an expected medical necessity denial (Modifier GA).
No valid ABN is obtained for an expected medical necessity denial (Modifier GZ).
A voluntary notice is issued under payer policy (Modifier GX).
Medicare provides coverage for the service under an applicable benefit category.

Medicare Rules

Under Medicare:

Modifier GY indicates that the item or service is not a Medicare benefit or is statutorily excluded.
An ABN is generally not required for services that are never covered because they fall outside Medicare’s benefit categories, although providers may choose to notify beneficiaries for transparency.
Claims submitted with Modifier GY are generally processed as non-covered services.
Medicare typically denies payment because the service is excluded by law rather than because it is not medically necessary.

Always review the current CMS Medicare Claims Processing Manual, National Coverage Determinations (NCDs), Local Coverage Determinations (LCDs), and Medicare Benefit Policy Manual.

Commercial Insurance Rules

Commercial insurance plans have their own benefit structures.

Many commercial insurers:

Do not recognize Modifier GY.
Apply their own non-covered service policies.
Use different denial processes.
Require prior authorization or benefit verification instead.

Always verify payer-specific billing instructions before using Medicare HCPCS liability modifiers on commercial claims.

Documentation Requirements

Documentation should include:

Physician order, when applicable.
Clinical documentation supporting the service provided.
Documentation explaining why the service falls outside Medicare’s covered benefits.
Applicable patient communication.
Medical record.
Provider signature where required.

Real Billing Examples

Example 1 – Cosmetic Procedure

A Medicare beneficiary elects to undergo a cosmetic procedure performed solely for aesthetic reasons.

The provider bills:

Appropriate CPT® code
Modifier GY

Because the procedure is statutorily excluded from Medicare coverage.

Example 2 – Routine Physical Examination

A beneficiary requests a routine annual physical examination that is not covered under a Medicare benefit category.

The provider submits:

Appropriate CPT® code
Modifier GY

Medicare denies payment because the service is excluded from coverage.

Example 3 – Personal Convenience Service

A provider furnishes a service that is considered a personal convenience item rather than a covered Medicare benefit.

Modifier GY is appropriate.

Example 4 – Incorrect Use

A medically necessary MRI is expected to be denied because the documentation does not satisfy the applicable LCD requirements.

Billing Modifier GY is incorrect.

The issue involves medical necessity, not a statutory exclusion. Modifier GA or GZ may be appropriate depending on whether a valid ABN was obtained.

CMS-1500 Claim Example

Field	Example
CPT® Code	Appropriate CPT® or HCPCS code
Modifier	GY
Diagnosis Pointer	Appropriate ICD-10-CM diagnosis
Charges	Provider’s usual charge

Common Denial Reasons

Service is statutorily excluded.
Service is not a Medicare benefit.
Incorrect liability modifier.
Wrong diagnosis coding.
Incorrect CPT® or HCPCS code.
Documentation inconsistent with the billed service.
Payer-specific policy differences.

How to Correct the Denial

Review the Medicare Remittance Advice.
Confirm that the service is truly statutorily excluded.
Verify the CPT®/HCPCS code and diagnosis coding.
Correct the modifier if the denial actually relates to medical necessity rather than statutory exclusion.
Appeal only if the service qualifies under an applicable Medicare benefit category or a coding error occurred.

Coding Tips

Use Modifier GY only for statutorily excluded or non-benefit services.
Understand the distinction between GY, GA, GX, and GZ.
Review Medicare benefit categories before claim submission.
Do not confuse coverage exclusions with medical necessity denials.
Verify payer-specific requirements for non-Medicare claims.

Modifier GY vs Modifier GA

Modifier	Description
GA	Valid ABN obtained for a service expected to be denied because it is not reasonable and necessary.
GY	Service is statutorily excluded or is not a Medicare benefit.

Modifier GY vs Modifier GZ

Modifier	Description
GY	Statutory exclusion or non-benefit.
GZ	Expected denial because the service is not reasonable and necessary and no valid ABN was obtained.

Modifier GY vs Modifier GX

Modifier	Description
GX	Voluntary notice of liability issued under payer policy.
GY	Statutorily excluded or non-benefit service.

Modifier GY vs Modifier KX

Modifier	Description
GY	Service is excluded from Medicare coverage.
KX	Requirements specified in the medical policy have been met.

Frequently Asked Questions (FAQs)

Q1. What does Modifier GY mean?

Answer: Modifier GY indicates that an item or service is statutorily excluded from Medicare coverage or does not meet the definition of any Medicare benefit.

Q2. Is an ABN required when Modifier GY is used?

Answer: Generally, no. Because the service is never covered by Medicare, a mandatory ABN is typically not required. However, providers may choose to notify beneficiaries for transparency or according to their internal policies.

Q3. What is the difference between Modifier GY and Modifier GZ?

Answer: Modifier GY is used when Medicare does not cover the service by law. Modifier GZ is used when the service could be a Medicare benefit but is expected to be denied because it is not considered reasonable and necessary.

Q4. Can Modifier GY be used for commercial insurance?

Answer: Modifier GY is primarily intended for Medicare claims. Commercial insurers usually have their own coverage policies and may not recognize this modifier.

AR Caller Tips

When following up on a denied Modifier GY claim:

Verify that the service is truly excluded from Medicare coverage.
Review applicable NCDs, LCDs, and Medicare benefit policies.
Confirm the correct liability modifier was reported.
Check whether the denial relates to coverage rather than medical necessity.
Record the payer representative’s name, reference number, and appeal instructions.

Interview Questions

Question 1

What is Modifier GY?

Answer: Modifier GY indicates that an item or service is statutorily excluded from Medicare coverage or does not meet the definition of a Medicare benefit.

Question 2

What is the difference between Modifier GY and Modifier GZ?

Answer: Modifier GY applies to services excluded from Medicare by law, while Modifier GZ applies to services expected to be denied because they are not reasonable and necessary and no valid ABN was obtained.

Question 3

Is an ABN generally required with Modifier GY?

Answer: No. Because the service is statutorily excluded, a mandatory ABN is generally not required, although providers may voluntarily notify the beneficiary.

Practice Scenario

Scenario

A Medicare beneficiary requests a cosmetic eyelid procedure performed solely for cosmetic purposes. The procedure is not covered because it is excluded from Medicare benefits.

Question

Which modifier should be reported?

Answer

The provider should report the appropriate CPT® code with Modifier GY, indicating that the service is statutorily excluded from Medicare coverage.

Related Modifiers

GA – Waiver of Liability Statement Issued as Required by Payer Policy (Valid ABN on File)
GX – Notice of Liability Issued, Voluntary Under Payer Policy
GZ – Item or Service Expected to Be Denied as Not Reasonable and Necessary (No ABN Obtained)
KX – Requirements Specified in the Medical Policy Have Been Met

Common Billing Mistakes

Using GY for medical necessity denials instead of GA or GZ.
Confusing statutory exclusions with non-covered services due to insufficient documentation.
Reporting GY on commercial insurance claims without payer guidance.
Incorrect CPT® or HCPCS coding.
Failing to verify Medicare benefit categories before billing.

Key Takeaways

Modifier GY identifies services that are statutorily excluded from Medicare coverage or do not meet the definition of a Medicare benefit.
It is different from GZ, which relates to medical necessity denials.
A mandatory ABN is generally not required because the service is never covered by Medicare.
Understanding Medicare benefit categories helps ensure proper use of Modifier GY.
Accurate documentation and correct modifier selection reduce claim errors and improve compliance.

References

CMS Medicare Claims Processing Manual, Chapter 30 – Financial Liability Protections.
CMS Medicare Benefit Policy Manual.
Medicare Learning Network (MLN) – Advance Beneficiary Notice (ABN) Booklet.
Medicare Administrative Contractor (MAC) billing guidance.
AMA CPT® Professional Edition (licensed codebook).

Conclusion

Modifier GY is an important Medicare coverage modifier used to identify items and services that are excluded from Medicare coverage by law or do not qualify as Medicare benefits. Correct use requires a clear understanding of Medicare benefit categories, statutory exclusions, and the distinction between coverage denials and medical necessity denials. Proper application of Modifier GY promotes compliant billing, accurate claim processing, and appropriate financial responsibility.

Educational Disclaimer

This article was prepared with the assistance of artificial intelligence (AI) for educational and informational purposes. It is based on publicly available CMS guidance, Medicare billing principles, and general medical coding practices. It is not an official publication of the American Medical Association (AMA), CMS, or any insurance payer. CPT® is a registered trademark of the American Medical Association. Always consult the latest AMA CPT® codebook, CMS Medicare Claims Processing Manual, Medicare Benefit Policy Manual, Medicare Learning Network (MLN) resources, Medicare Administrative Contractor (MAC) policies, and payer-specific billing requirements before coding, billing, or submitting claims.