2026 ICD-10-CM Diagnosis Code Z17.31Human epidermal growth factor receptor 2 positive status

ICD-10-CM Codes›Z00–Z99›Z17›Z17

ICD-10-CM Z17.31
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Z17.31 is a billable ICD-10-CM diagnosis code for human epidermal growth factor receptor 2 positive status. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026). The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Genetic susceptibility to disease.

Code Identity

ICD-10-CM Code
Z17.31
Billable Status
Yes — Valid for Submission
Code Describes
Human epidermal growth factor receptor 2 positive status
Short Description
Human epidermal growth factor receptor 2 positive status
Same as the full description in the CMS dataset.
Parent Code
Z17.3
Human epidermal growth factor 2 receptor

Code Classification

ChapterZ00–Z99Factors influencing health status and contact with health services
SectionZ17Estrogen, and other hormones and factors receptor status
CategoryZ17Estrogen, and other hormones and factors receptor status
This CodeZ17.31Human epidermal growth factor receptor 2 positive status

Code EditsBilling

Medicare Code Editor checks that affect claim validity for Z17.31.

Unacceptable principal diagnosis
There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Present on Admission (POA)Billing

Z17.31 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • HER2+

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Status(post)
      • human epidermal growth factor 2 receptor
        • positive

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR FAC029
Genetic susceptibility to disease
Default principal diagnosis: inpatient No · outpatient No

Code HistoryHistory

FY 2025AddedAdded to the ICD-10-CM code setEffective October 1, 2024.
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Z17.31Overview

Is Z17.31 (Human epidermal growth factor 2 receptor) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report human epidermal growth factor receptor 2 positive status on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

Can Z17.31 be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because human epidermal growth factor receptor 2 positive status describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

Is Z17.31 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for human epidermal growth factor receptor 2 positive status on inpatient claims.