Z17.421 — Hormone receptor negative with human epidermal growth factor receptor 2 negative status
Is Z17.421 billable?
Yes — Z17.421 is billable for FY2027. Z17.421 is a valid, billable ICD-10-CM code at the highest level of specificity in its branch. Z17.421 may be submitted for encounters from October 1, 2026 through September 30, 2027.
Z17.421 at a glance
| Code | Z17.421 |
|---|---|
| Description | Hormone receptor negative with human epidermal growth factor receptor 2 negative status |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
What Medicare edits apply to Z17.421?
The Medicare Code Editor screens inpatient claims before they are grouped. These edits name Z17.421 directly.
CMS will reject this code as the principal diagnosis on an inpatient claim. It describes something other than the condition chiefly responsible for the admission.
Which MS-DRGs does Z17.421 group to?
Z17.421 sits in MDC 23 and helps define the logic of 1 MS-DRG (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 951Other Factors Influencing Health Statusmedical
How is Z17.421 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to Z17.421. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Triple › negative breast cancer
- Status › combined receptor › negative › hormone receptor negative with human epidermal growth factor receptor 2 negative (post)
Inclusion terms
Alternative wording in documentation that is classified to Z17.421.
- HR- with HER2-
- TNBC
- Triple negative breast cancer
Code first — inherited from Z17
The underlying condition below must be sequenced before Z17.421. Z17.421 describes a manifestation and cannot be the principal or first-listed diagnosis.
How long has Z17.421 existed?
Z17.421 first appears in FY2025.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.