G9831 — Ajcc stage at breast cancer diagnosis = ii or iii
G9831 is a HCPCS Level II code for ajcc stage at breast cancer diagnosis = ii or iii. It belongs to the Procedures and Professional Services (Temporary) section. Whether Medicare pays it depends on the coverage rule below.
Medicare coverage: Carrier judgment
Coverage is decided by your Medicare contractor, not by national policy. Whether this is paid depends on the LCD for your jurisdiction and on what the documentation supports.
From the coverage field of the CMS Alpha-Numeric HCPCS File, release 2026Q3-Jul. This states Medicare’s position on the code, not on your particular claim.
Physician fee schedule statusM
Measurement code. Used for reporting purposes only; never paid.
Global period: XXX
Want the dollar amount for your locality? The fee calculator applies your GPCI and the current conversion factor.
The CMS record for G9831
- Long descriptor
- Ajcc stage at breast cancer diagnosis = ii or iii
- Short descriptor
- Ajcc stg brt ca dx ii or iii
- Added
- January 1, 2017
- BETOS
- Z2
- Pricing indicator
- 00 — Not priced by Part B
The official wording. This is what the code means.
CMS's 28-character form, which is what shows up on a remittance advice.
When CMS introduced the code.
Berenson-Eggers Type of Service — CMS's own analytic grouping.
Service not separately priced by Part B — not covered, bundled into another service, or used by Part A only.
Codes adjacent to G9831
HCPCS has no hierarchy — related items simply sit next to each other in the numbering. If G9831 is not quite right, the correct code is very often within a few positions of it.
- G9823Endometrial sampling or hysteroscopy with biopsy and results documented during the 12 months prior to the index date (exclusive of the index date) of the endometrial ablation
- G9824Endometrial sampling or hysteroscopy with biopsy and results not documented during the 12 months prior to the index date (exclusive of the index date) of the endometrial ablation
- G9825Her-2/neu negative or undocumented/unknownterminated
- G9826Patient transferred to practice after initiation of chemotherapyterminated
- G9827Her2-targeted therapies not administered during the initial course of treatmentterminated
- G9828Her2-targeted therapies administered during the initial course of treatmentterminated
- G9829Breast adjuvant chemotherapy administeredterminated
- G9830Her-2/neu positive
- G9832Ajcc stage at breast cancer diagnosis = i (ia or ib) and t-stage at breast cancer diagnosis = t1c
- G9833Patient transfer to practice after initiation of chemotherapyterminated
- G9834Patient has metastatic disease at diagnosisterminated
- G9835Trastuzumab administered within 12 months of diagnosisterminated
- G9836Reason for not administering trastuzumab documented (e.g. patient declined, patient died, patient transferred, contraindication or other clinical exclusion, neoadjuvant chemotherapy or radiation not complete)terminated
- G9837Trastuzumab not administered within 12 months of diagnosisterminated
- G9838Patient has metastatic disease at diagnosis
- G9839Anti-egfr monoclonal antibody therapy
Questions about G9831
What is HCPCS code G9831?
G9831 is a HCPCS Level II code for ajcc stage at breast cancer diagnosis = ii or iii. It sits in the Procedures and Professional Services (Temporary) section.
Does Medicare cover G9831?
The CMS HCPCS file marks G9831 as "Carrier judgment". Coverage is decided by your Medicare contractor, not by national policy. Whether this is paid depends on the LCD for your jurisdiction and on what the documentation supports.
How is G9831 paid under the physician fee schedule?
G9831 carries PFS status code M. Measurement code. Used for reporting purposes only; never paid.