GS HCPCS Level II modifier: Dosage of erythropoietin stimulating agent has been reduced and maintained in response to hematocrit or hemoglobin level

GS is a HCPCS Level II modifier: “Dosage of erythropoietin stimulating agent has been reduced and maintained in response to hematocrit or hemoglobin level.” It adds this detail to the code it is reported with.

Official description

GS

Dosage of erythropoietin stimulating agent has been reduced and maintained in response to hematocrit or hemoglobin level

Short description: Epo/darbepoietin reduced 25%

HCPCS · United States

Medicare details

The indicators CMS publishes with GS in its October 2026 file. They describe Medicare’s handling, not another payer’s.

Medicare coverage: Special coverage instructions apply
Added: Jan 1, 2006

Where GS sits

1GroupHCPCS modifiers
2Modifier GSDosage of erythropoietin stimulating agent has been reduced and maintained in response to hematocrit or hemoglobin level

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.

See GS in the CMS source

Frequently asked questions

What does HCPCS code GS mean?

GS is the HCPCS code for “Dosage of erythropoietin stimulating agent has been reduced and maintained in response to hematocrit or hemoglobin level” in CMS’s HCPCS Level II October 2026 release.

Where is GS in the HCPCS Level II list?

GS is listed under Modifiers.

Does Medicare cover GS?

CMS lists GS’s Medicare coverage as “Special coverage instructions apply”. 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.

All modifiers

GMMultiple patients on one ambulance trip GNServices delivered under an outpatient speech language pathology plan of care GOServices delivered under an outpatient occupational therapy plan of care GPServices delivered under an outpatient physical therapy plan of care GQVia asynchronous telecommunications system GRThis service was performed in whole or in part by a resident in a department of veterans affairs medical center or clinic, supervised in accordance with va policy GTVia interactive audio and video telecommunication systems GUWaiver of liability statement issued as required by payer policy, routine notice GVAttending physician not employed or paid under arrangement by the patient's hospice provider GWService not related to the hospice patient's terminal condition GXNotice of liability issued, voluntary under payer policy GYItem or service statutorily excluded, does not meet the definition of any medicare benefit or, for non-medicare insurers, is not a contract benefit