Modifier GA- Waiver of Liability Statement Issued

Indicates that a mandatory Advance Beneficiary Notice of Noncoverage (ABN) was issued as required before furnishing a service for which Medicare payment may be denied.

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What Is Modifier GA?

Modifier GA is a Medicare liability modifier defined as “Waiver of Liability Statement Issued, as Required by Payer Policy.”

It is reported when a provider, practitioner, or supplier properly issues a mandatory Advance Beneficiary Notice of Noncoverage (ABN) for an item or service and keeps the notice on file.

The ABN informs the Medicare beneficiary before the service is furnished that Medicare may not pay and explains the beneficiary's potential financial responsibility. CMS instructs providers to report GA when a mandatory ABN is required and has been issued.

Modifier GA is therefore primarily a liability and claim-reporting modifier. It does not make a service medically necessary or guarantee Medicare payment.

When to Use Modifier GA

Mandatory ABN Issued: A valid mandatory ABN was provided to the beneficiary as required before the applicable item or service was furnished.

Payment Is Expected to Be Denied: The provider expects Medicare may deny an otherwise potentially covered service under circumstances requiring an ABN.

ABN Kept on File: The completed notice is retained in the provider's records. CMS states that a copy does not ordinarily need to accompany the claim but must be available upon request.

ABN-Related Claim: CMS specifically instructs providers to use GA when covered and noncovered services appear on an ABN-related claim.

Beneficiary Liability Is Relevant: GA communicates that the required advance notice process was followed so beneficiary liability can be determined under Medicare rules.

When NOT to Use Modifier GA

No ABN Was Issued: If Medicare payment is expected to be denied as not reasonable and necessary but a required ABN was not issued, GZ generally describes that situation instead.

Voluntary Notice: GX is used when a voluntary notice of liability is issued for a service Medicare never covers because it is statutorily excluded or is not a Medicare benefit.

Statutorily Excluded Service: GY identifies an item or service that is statutorily excluded or does not meet the definition of a Medicare benefit.

ABN Issued After the Service: GA should not be used to correct an ABN that was improperly delivered after the beneficiary had already received the service.

Invalid ABN: Merely having an ABN form in the record does not support GA if the notice fails Medicare's applicable requirements.

Routine Use on Every Claim: GA should not be automatically appended simply because a service might be denied.

Billing Example

A Medicare beneficiary is scheduled to receive a service that is ordinarily covered but may not meet Medicare's applicable medical-necessity requirements in this individual case.

Before providing the service, the provider gives the beneficiary a properly completed mandatory ABN explaining why Medicare may not pay and the beneficiary's potential financial responsibility.

The beneficiary makes the applicable election, and the provider retains the completed ABN.

The service is then reported with Modifier GA to indicate that the required notice was issued.

GA does not force Medicare to deny or pay the service. Medicare still processes the claim and makes the applicable coverage determination. CMS guidance describes GA as linking the line item to the mandatory ABN process.

Documentation Requirements

Completed ABN: Maintain the properly completed Advance Beneficiary Notice of Noncoverage in the beneficiary's record.

Advance Delivery: Documentation should establish that the ABN was delivered before the applicable item or service was furnished.

Reason for Expected Noncoverage: The notice should clearly explain why Medicare is expected not to pay.

Beneficiary Election: Maintain the beneficiary's applicable selection and acknowledgment according to ABN requirements.

Service Identification: The ABN should clearly identify the item or service involved.

Supporting Medical Record: Clinical documentation should support the service furnished and the circumstances that led to the expected coverage issue.

CMS states that the ABN generally does not need to be submitted with the claim, but providers must make it available upon request.

Billing and Claim Considerations

Modifier GA does not mean that Medicare has already denied the service.

It tells Medicare that a required ABN was issued and retained. Medicare can then adjudicate the underlying item or service according to applicable coverage and payment rules.

CMS guidance indicates that GA is used with a mandatory ABN, while GX, GY, and GZ represent different liability circumstances. Selecting the correct modifier is important because the choice can affect how Medicare determines financial liability.

Providers should also avoid treating GA as a substitute for proper documentation. The underlying service still needs appropriate diagnosis coding, medical documentation, and compliance with applicable Medicare coverage rules.

For certain Part A MAC claims, CMS coverage articles state that occurrence code 32 and the ABN date are required when GA is reported.

Understanding the Medicare ABN Process

An ABN is intended to give an Original Medicare beneficiary meaningful advance notice that Medicare may not pay for a particular item or service.

The notice allows the beneficiary to understand the potential financial consequences and make an informed decision before receiving the service.

If a provider fails to issue a required ABN—or Medicare determines that the notice was invalid—the provider may be financially liable instead of the beneficiary. CMS also states that improperly collected beneficiary payments may need to be refunded.

That makes correct ABN delivery just as important as adding GA to the claim.

Modifier GA vs. Modifier GZ

Modifier GA: A mandatory ABN was issued as required and is on file.

Modifier GZ: The provider expects Medicare to deny the item or service as not reasonable and necessary, but an ABN was not issued.

This distinction directly affects liability considerations.

GA should not be replaced with GZ merely because both modifiers may involve an anticipated Medicare denial. The determining factor is whether the required ABN process was properly completed.

Modifier GA vs. Modifier GX

Modifier GA: Used when a mandatory ABN is issued as required.

Modifier GX: Used when a voluntary notice of liability is issued for an item or service Medicare never covers because it is statutorily excluded or is not a Medicare benefit.

The distinction is important because GA and GX represent different notice and coverage circumstances.

Common Billing Mistakes

No Valid ABN on File: Reporting GA without having properly issued and retained the required ABN can create liability problems.

ABN Issued Too Late: Giving the notice after the service does not satisfy the purpose of advance notification.

Using GA Instead of GZ: GA should not be reported when an expected medical-necessity denial occurs without the required ABN.

Using GA for Statutory Exclusions: GY, and in applicable voluntary-notice circumstances GX, may be more appropriate for services Medicare excludes by statute or does not recognize as benefits.

Assuming GA Guarantees Beneficiary Liability: Liability depends on whether Medicare's notice requirements were properly satisfied, not simply whether GA appears on the claim.

Using GA to Establish Medical Necessity: GA addresses liability notification. It does not make an otherwise unsupported service medically necessary.

Common Denial Reasons

Underlying Service Not Covered: Medicare determines that the item or service does not satisfy applicable coverage requirements.

Medical Necessity Requirements Not Met: Documentation does not support the service under applicable Medicare policy.

Invalid ABN: The notice does not satisfy Medicare's ABN requirements.

Incorrect Liability Modifier: The circumstances support GZ, GX, or GY rather than GA.

Insufficient Documentation: The record does not support the billed service or expected coverage issue.

Claim Reporting Error: Required claim information associated with the service or applicable ABN reporting rules is incomplete or incorrect.

Frequently Asked Questions

Does Modifier GA automatically make the beneficiary responsible for payment?
No. GA reports that a mandatory ABN was issued as required, but simply adding the modifier does not override Medicare's notice and liability requirements. The ABN must be valid and properly delivered, and Medicare still adjudicates the claim under applicable rules.

Does the ABN need to be submitted with a claim containing Modifier GA?
Generally, no. CMS instructs providers to keep the mandatory ABN on file rather than routinely submit it with the claim, but it must be available if requested.