GK HCPCS Level II modifier: Reasonable and necessary item/service associated with a ga or gz modifier
GK is a HCPCS Level II modifier: “Reasonable and necessary item/service associated with a ga or gz modifier.” It adds this detail to the code it is reported with.
Official description
GKReasonable and necessary item/service associated with a ga or gz modifier
Short description: Actual item/service ordered
HCPCS · United States
Medicare details
The indicators CMS publishes with GK in its October 2026 file. They describe Medicare’s handling, not another payer’s.
- Medicare coverage
- Carrier judgment
- Added
- Jan 1, 2002
Where GK sits
- 1GroupHCPCS modifiers
- 2Modifier GKReasonable and necessary item/service associated with a ga or gz modifier
Source and release
- Data release
- HCPCS Level II · October 2026
- Effective date
- Oct 1, 2026
- Publisher
- CMS
This page is built from the HCPCS Level II catalog that Vero Codes reads when it suggests codes: Centers for Medicare & Medicaid Services’s October 2026 release, imported from the publisher’s file and checked against it. The description, notes and structured data come from the same record.
Frequently asked questions
What does HCPCS code GK mean?
GK is the HCPCS code for “Reasonable and necessary item/service associated with a ga or gz modifier” in CMS’s HCPCS Level II October 2026 release.
Where is GK in the HCPCS Level II list?
GK is listed under Modifiers.
Does Medicare cover GK?
CMS lists GK’s Medicare coverage as “Carrier judgment”. Coverage and payment still depend on the patient, the setting, the documentation and the payer.
Which HCPCS Level II release does this page use?
It uses CMS’s October 2026 release, in effect from Oct 1, 2026 to Dec 31, 2026. It is a reference: confirm the code against the current list and the payer’s rules before you submit it.
Codes beside GK
All modifiersGDUnits of service exceeds medically unlikely edit value and represents reasonable and necessary servicesGEThis service has been performed by a resident without the presence of a teaching physician under the primary care exceptionGFNon-physician (e.g. nurse practitioner (np), certified registered nurse anesthetist (crna), certified registered nurse (crn), clinical nurse specialist (cns), physician assistant…GGPerformance and payment of a screening mammogram and diagnostic mammogram on the same patient, same dayGHDiagnostic mammogram converted from screening mammogram on same dayGJ"opt out" physician or practitioner emergency or urgent serviceGLMedically unnecessary upgrade provided instead of non-upgraded item, no charge, no advance beneficiary notice (abn)GMMultiple patients on one ambulance tripGNServices delivered under an outpatient speech language pathology plan of careGOServices delivered under an outpatient occupational therapy plan of careGPServices delivered under an outpatient physical therapy plan of careGQVia asynchronous telecommunications system