HCPCS Level II modifier
Modifier GD
Modifier GD is a HCPCS Level II modifier. CMS describes it as: Units of service exceeds medically unlikely edit value and represents reasonable and necessary services.
Source: CMS HCPCS Level II, October 2026 file dated September 23, 2026. Publisher page
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- Modifier
- GD
- Type
- HCPCS Level II modifier, maintained by CMS
- CMS description
- Units of service exceeds medically unlikely edit value and represents reasonable and necessary services
- Claim form
- CMS-1500 item 24D, up to four modifiers per line. 837P SV101-3 to SV101-6.
- Guidance
- CMS HCPCS quarterly update
Related modifiers
- GEThis service has been performed by a resident without the presence of a teaching physician under the primary care exception
- GCThis service has been performed in part by a resident under the direction of a teaching physician
- GFNon-physician (e.g. nurse practitioner (NP), certified registered nurse anesthetist (CRNA), certified registered nurse (CRN), clinical nurse specialist (CNS), physician assistant (PA)) services in a critical access hospital
- GBClaim being re-submitted for payment because it is no longer covered under a global payment demonstration
- GGPerformance and payment of a screening mammogram and diagnostic mammogram on the same patient, same day
- GAWaiver of liability statement issued as required by payer policy, individual case
- GHDiagnostic mammogram converted from screening mammogram on same day
- G9Monitored anesthesia care for patient who has history of severe cardio-pulmonary condition
Related pages
Questions
What does modifier GD mean?
Modifier GD is a HCPCS Level II modifier. CMS describes it as: Units of service exceeds medically unlikely edit value and represents reasonable and necessary services.
Is modifier GD a CPT or a HCPCS modifier?
GD is a HCPCS Level II modifier from the CMS quarterly HCPCS file. Two-digit numeric modifiers, such as 25 or 59, are CPT modifiers.
Where does modifier GD go on a claim?
On the CMS-1500 it goes in item 24D next to the procedure code. Each line holds up to four modifiers. On an 837P it goes in SV101-3 to SV101-6.
What denial comes back when a modifier is wrong?
A missing or mismatched modifier often comes back as CARC 4. A modifier that was not valid on the date of service comes back as CARC 182. A bundling edit the modifier should have bypassed comes back as CARC 97 or 236.