A Medicare patient comes in for a routine hearing exam. You know Medicare won’t cover it. Do you skip billing altogether? Bill the patient directly without any documentation? Or submit a claim with the right modifier to protect your practice, trigger a clean denial, and open the door for secondary insurance recovery?
The answer is the GY modifier, and using it correctly is the difference between a compliant claim and a costly billing mistake.
What Is the GY Modifier in Medical Billing?
The GY modifier is a two-character HCPCS modifier. It is appended to a CPT or HCPCS code to indicate that an item or service is statutorily excluded from Medicare coverage. That means Medicare will never cover it under any circumstance, regardless of medical necessity.
According to CMS and MAC guidance, the GY modifier signals that the service “does not meet the definition of any Medicare benefit.”
When you append the GY modifier, Medicare automatically denies the claim. That denial then allows you to bill the patient directly or forward the claim to a secondary insurer.
One critical distinction: statutory exclusions are not the same as medical necessity denials. “Statutory” means written into federal law. These are services. Congress explicitly removed it from Medicare’s benefit structure, not services that might be covered if documented better.
6 Services That Require the GY Modifier
These are the most common legally excluded services that providers submit with the GY modifier:
- Routine dental care
- Routine eye exams
- Hearing aids and hearing exams
- Cosmetic procedures
- Personal comfort items
- Services rendered outside the United States
These exclusions are stable in 2026.
Important 2026 Note: CMS has expanded limited dental exceptions for services “inextricably linked” to a covered Medicare procedure, but these require documented care coordination between providers. Routine dental exclusions still apply. Misclassifying an inextricably linked service as routine GY can trigger a compliance audit.
How the GY Modifier Works: Step-by-Step
Follow these 5 steps.
Identify a statutory exclusion
Confirm that the service is not a Medicare benefit by statute, not merely one that might be denied for medical necessity.
Append “GY” to the CPT or HCPCS code
Place GY in the modifier field on the claim. It can be used on Part B professional claims and in certain institutional billing scenarios.
Submit to Medicare
The claim will generate an automatic denial. This is intentional. You are not “trying” to get Medicare to pay. You are creating a documented denial.
Use the denial for secondary billing
The Medicare denial EOB (Explanation of Benefits) is often required by a secondary insurer before they will process the claim. The GY modifier accelerates this process because it produces a fast, clean denial.
Bill the patient or secondary payer
Financial responsibility shifts fully to the beneficiary, either out-of-pocket or through their secondary insurer.
GY Modifier and Secondary Insurance: Why This Step Matters
One of the most practical and most overlooked reasons to use the GY modifier is secondary payer billing.
Many Medicare beneficiaries carry supplemental coverage, such as Medigap plans, employer retiree insurance, or Medicaid. Some of those plans will cover services Medicare excludes. But they often require a Medicare denial on file before processing the claim.
When a beneficiary wants a denial through Medicare for secondary payer purposes, the claim should be submitted with the GY modifier. This allows the claim to be processed faster than it would be without the modifier.
Without the GY modifier, the denial may be coded differently or take longer. With it, the denial is clean, fast, and clearly coded as a statutory exclusion, exactly what most secondary insurers need to proceed.
When Medicare denies the claim with the GY modifier, the provider can then bill the patient or secondary insurer. The modifier signals the denial reason without changing the fact that Medicare will not pay.
Table: GY Modifier vs. GA, GX, and GZ: Comparison
| Modifier | Meaning | ABN Required? | Patient Liable? | Use Case |
| GY | Statutorily excluded, not a Medicare benefit | No | Yes | Routine dental, vision, cosmetic, and hearing |
| GA | ABN on file; service may be denied for medical necessity | Yes (mandatory) | Yes (if denied) | Services that may lack medical necessity documentation |
| GX | Voluntary ABN issued; service is non-covered | Yes (voluntary) | Yes | Patient-requested non-covered services |
| GZ | Service expected to be denied; no ABN issued | No (and that’s the problem) | No, the provider liable | Billing error scenario: avoid this outcome |
Never use GY and GZ on the same claim line. Never use GY for a service that might be covered under some circumstances; that is a compliance error.
Does the GY Modifier Require an ABN?
No. An ABN is not required when using the GY modifier.
The ABN, specifically CMS Form CMS-R-131, is a tool for services. That might be covered but could be denied for medical necessity. It is part of the GA and GX modifier workflow.
Statutory exclusions operate differently. Because Medicare never covers these services under any condition, the ABN framework does not apply. The financial responsibility shifts to the patient automatically, by law, without a signed ABN.
4 Common GY Modifier Billing Errors to Avoid
Avoid making these mistakes.
- Using GY for a medical necessity denial: GY is for statutory exclusions only. If a service could be covered under the right circumstances, use GA (with ABN) or GZ (no ABN). Applying GY to a borderline medical necessity case is a compliance error and can result in audit exposure.
- Applying GY to bundled procedures or add-on codes: The GY modifier cannot be used on bundled procedures or on add-on codes. These are subject to different billing rules entirely.
- Confusing GY with GX: GX is used when a provider issues a voluntary ABN, meaning the patient asked for the service and was informed it would not be covered. GY does not require any ABN. Using GX instead of GY (or vice versa) creates claim processing errors.
- Misapplying GY to inextricably linked dental services: In 2026, CMS recognizes a narrow exception for dental services integral to a covered Medicare procedure. Those claims require documented care coordination, not a GY modifier. Submitting these with GY triggers incorrect denials and shifts costs inappropriately.
GY Modifier and Medicare Advantage Plans
Medicare Advantage (MA) plans operate under separate billing rules. The GY modifier, like the GA modifier, is designed for Original Medicare (Part B) fee-for-service billing.
MA plans have their own noncoverage notification processes. Applying GA or similar modifiers to an MA claim does not shift liability and may result in claim processing errors.
For MA members, providers should follow the specific plan’s non-covered service notification requirements. Some plans, including certain UnitedHealthcare MA products, have introduced hybrid modifier rules. Verify with each plan before applying GY to an MA claim.
GY Modifier in 2026: What Has Changed
The GY modifier itself has not changed in 2026. Its definition, use cases, and billing rules remain consistent.
What has changed is the financial pressure around using it correctly. CMS’s CY 2026 MPFS materials describe updated conversion factors and a finalized -2.5% efficiency adjustment applied to many non-time-based services. For billing operations, this makes denial prevention and clean secondary billing pathways higher yield than before.
In a tighter reimbursement environment, every clean denial that opens a secondary billing pathway has a more direct revenue impact. Getting GY right is not a technicality; it is a revenue protection strategy.
Stop Losing Revenue to Preventable Modifier Errors
The GY modifier protects your practice from write-offs on non-covered services and speeds up secondary insurance recovery. Used incorrectly or not used at all, it leaves revenue on the table, shifts liability back to the provider, and creates audit risk.
Medicare modifier mistakes are one of the most common and most fixable sources of claim denials in physician practices. At Maine Billing Services, we handle the details that matter, including modifier accuracy on every claim. Our billing specialists apply the correct modifiers on every claim, every time.
Frequently Asked Questions
- Can GY and GX be used together on the same claim line?
Yes. GX and GY can be combined in certain cases, specifically when a provider issues a voluntary ABN for a statutorily excluded service to document patient awareness. This combination is allowed. However, GY should never be combined with GA or GZ on the same claim line.
- Does using the GY modifier protect the provider from liability?
Yes. When the GY modifier is correctly applied to a statutorily excluded service, financial liability shifts fully to the beneficiary, either through out-of-pocket payment or through their secondary insurer. The provider is not held responsible for the uncollected amount under Medicare’s limitation on liability provisions.
- Can the GY modifier be used for telehealth services?
Only in limited circumstances. GY is sometimes misapplied to telehealth claims when coverage is denied due to policy constraints, for example, site-of-service restrictions, rather than a statutory exclusion. A telehealth denial for policy reasons is not the same as a statutory exclusion. Using GY in that context is incorrect and can trigger audits.
- What happens if a provider submits a GY claim for a service that is actually covered?
Medicare will deny the claim as statutorily excluded. The provider loses the opportunity for reimbursement and cannot later refile correctly with the original date of service in most cases. This is a significant revenue loss and a documentation compliance risk. Always confirm statutory exclusion status before appending GY.
- Is the GY modifier used differently for institutional versus professional billing?
The core meaning is the same. However, institutional billing (UB-04) has additional steps. For totally non-covered claims where all services are statutorily excluded, condition code 21 is used at the claim level, and the GY modifier is not required on individual lines. For mixed claims with both covered and non-covered services, GY is appended to the non-covered line items.