What Is the GZ Modifier in Medical Billing?
The GZ modifier is a two-letter code used in medical billing. It shows that a provider or supplier thinks Medicare will deny a service or item. They have not gotten a signed Advance Beneficiary Notice (ABN) from the patient.
In simple terms, GZ = No ABN, Likely Denial.
The modifier GZ is a flag that says: “We believe Medicare won’t pay for this, and we didn’t warn the patient.”
GZ Modifier Meaning and Purpose
Key Points
- Used only for Medicare billing.
- Indicates likely denial of payment.
- The patient did not issue or sign any ABN.
- The provider cannot bill the patient for the denied service.
Example
A provider performs a routine foot care service for a Medicare patient. They did not issue an ABN, even though they expected the service denial. The provider submits the claim with the GZ modifier.
Result: Medicare denies the claim, and the provider must absorb the cost.
Also Read: Correct Billing Instructions And Usage for GA Modifier
When to Use Modifier GZ?
Common Scenarios
| Service | ABN Given? | Use GZ Modifier? |
| Routine foot care | No | Yes |
| Screening test (non-covered) | No | Yes |
| Cosmetic service | No | Yes |
| Covered diagnostic test | Not applicable | No |
Practical Rule
Use the GZ modifier when:
- You expect Medicare will deny the claim.
- You did not issue or collect a signed ABN.
- You want to comply with Medicare’s billing rules, but won’t bill the patient.
Modifier GZ vs. GA vs. GY
Comparison Table
| Modifier | Definition | ABN Required? | Used For |
| GZ | Expected denial, no ABN on file | No | Medicare non-compliance |
| GA | Expected denial, ABN signed | Yes | Medicare covered service |
| GY | Statutorily excluded service | No | Always excluded items |
Important Notes
- GZ = No ABN, and the provider can’t collect payment.
- GA = ABN is provided, the patient may be responsible.
- GY = The law does not cover the service; the provider can bill the patient.
Why Use the GZ Modifier?
Benefits of Accurate Use
- Signals to Medicare that no ABN was given.
- Ensures transparency and compliance with CMS rules.
- Documents that the provider is not billing the patient.
- Helps maintain billing integrity and avoid audits.
Tip: The GZ modifier helps protect the patient. It also keeps the provider following Medicare rules, even if it leads to non-payment.
Billing Process with the GZ Modifier
- Assess Service: Determine that the item/service is likely not payable by Medicare.
- Confirm No ABN: No notice was provided to the patient.
- Append Modifier GZ: Add GZ to the relevant CPT/HCPCS code.
- Submit Claim: Expect an automatic denial from Medicare.
- Do Not Bill Patient: The provider must absorb the cost.
Example Usage
- CPT Code: 11720 – Debridement of nails
- Scenario: Routine nail care with no ABN.
- Billing: Submit as 11720-GZ. Expect denial.
Common Mistakes with Modifier GZ
Using GZ with ABN on File
- If an ABN is provided and signed, use GA, not GZ.
Applying GZ for Covered Services
- Never use GZ for services that Medicare covers normally, with proper documentation.
Expecting Payment
- The GZ modifier is a flag for denial. Medicare will not pay, and you cannot bill the patient.
Mixing GZ with GY
- GY is used when a service is legally excluded from Medicare. GZ applies when it’s potentially covered, but the team failed to meet compliance.
Also Read: Correct Billing Instructions And Usage for GY Modifier
Best Practices
- Train staff to identify when an ABN is needed.
- Use the GZ modifier only when documentation is lacking.
- Always expect $0 reimbursement when using GZ.
- Review CMS coverage policies regularly to avoid misapplication.
FAQs
What is a GZ modifier?
The GZ modifier tells Medicare that you expect a denial. It also means you did not get the patient’s signature on an ABN form. It applies only to Medicare and indicates non-compliance.
Does GZ mean the provider can bill the patient?
No. When the GZ modifier is used, the provider cannot bill the patient for the denied service, since no ABN was given in advance.
What’s the difference between the GZ and GA modifiers?
GZ means that someone did not provide an ABN, and they do not expect payment. GA means that someone signed an ABN, so the provider may bill the patient if Medicare denies the claim.
Is the GZ modifier only for Medicare?
Yes. The GZ modifier applies specifically to Medicare billing and does not appear in commercial insurance claims.
What happens if I forget to use GZ on a likely denied claim?
If you skip the GZ modifier, Medicare may delay processing or question compliance. It’s better to use GZ to show you understand the rules and aren’t seeking payment.
Final Thoughts
The GZ modifier is an essential billing tool when compliance falls short. It makes your intent clear—Medicare won’t pay, and you’re not billing the patient. Though it results in denial, using the GZ modifier shows transparency and accountability. For clear and correct billing, always use the right modifier.
Use GZ when there is no ABN on file. Use GA when you have an ABN. Use GY for services that law excludes.
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