Q&A: Modifier -GD with MUE edits

Q: I have heard of a modifier -GD in relation to the Medically Unlikely Edits (MUE). What is the definition of this modifier and how is it used?

A: Modifier -GD means units in excess of the MUE limit. It would be wonderful if CMS recognized that modifier, which has already been defined and is published and accepted as a HCPCS level two modifier in terms of being in the book and having a definition. However, Medicare has not acknowledged that modifier for billing. Therefore, there is no instruction from CMS. There’s no indication in the NCCI policy manual or in a transmittal from Medicare that providers can add modifier -GD to bypass the unit limit to make the claim process and pay.

I think that that’s a great question to ask CMS or the contractor, because modifier -GD does exist, and it’s been published. I think it would be a great way to resolve some of these problems if providers were able to affix that modifier.

CMS could ensure that modifier -GD is used correctly by requiring providers to attest when they use the modifier.

For more information, see Medicare Billing Edits: A Guide to Regulation, Research, and Resolution.

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