What is a Modifier?
A coding modifier is often used when billing health insurance companies. It provides additional information about the procedure code being used, without altering the definition of the code.
If billing on a CMS1500 form, modifiers go in box 24D, to the right of the CPTⓇ code. There is space available for up to four modifiers.
GX Modifier Definition
The GX modifier is defined as, “item or service expected to be denied as not reasonable and necessary.”
When to Use the GX Modifier
If a Medicare patient is receiving a service that is not a Medicare benefit or has never been covered by Medicare because they deem it statutorily excluded, having the patient fill out an Advance Beneficiary Notice (ABN), is not required. However, if a voluntary ABN was issued, the GX modifier can be used.
This modifier can be combined with the GY modifier.
ABN forms can be obtained via the Center for Medicare & Medicaid Services (CMS) website.
Other ABN Claim Reporting Modifiers
- GA Modifier – “Waiver of Liability Statement Issued, as Required by Payer Policy”
- GZ Modifier – “Item or Service Expected to Be Denied as Not Reasonable and Necessary”
- GY Modifier – “Item or Service Statutorily Excluded or Does Not Meet the Definition of Any Medicare Benefit”