When submitting a COB (Coordination of Benefits) claim to Quartz after Medicare or another primary payer, it is important that your G modifier use (GY, GZ, GA, GX) is reviewed. While these modifiers may be appropriate for initial Medicare submission, they may not be appropriate with claims submitted to Quartz as a secondary payer.
Quartz utilizes CMS coding guidelines. As a result, the use of G modifiers will deny services they are appended to.
Although Medicare may consider a service non-covered, Quartz may cover it under the member’s plan. When a claim is submitted with a G modifier, the provider is stating the service isn’t covered, and we will not consider that service for payment.
Submitting G modifiers can trigger unnecessary denials.
What to do instead:
- Submit your COB claims to Quartz without GY, GZ, GA, GX, or similar modifiers when appropriate.
- Allow our plan benefits to determine whether the service is payable.
| Modifier | Meaning | Why it’s a problem |
| GY | Service is statutorily excluded/not a Medicare benefit | Quartz may cover it, but if GY is present the line will receive a denial |
| GZ | Provider expects denial, no ABN given | You are presuming non-payment |
| GA | ABN on file for non-covered service | Not relevant unless it affects benefit determination |
| GX | ABN on file for service never covered | Request for denial |
**Quartz may conduct post-payment audits of claims submitted directly by Medicare for appropriate payment.
Please refer to the Provider Manual for further details on COB billing.
