Z17.421 Hormone receptor negative with human epidermal growth factor receptor 2 negative status
Billable ICD-10-CM code, FY2026. Exempt from present-on-admission (POA) reporting.
Applicable to
HR- with HER2-
TNBC
Triple negative breast cancer
Applies from Z17 Estrogen, and other hormones and factors receptor status
Code first
malignant neoplasm, such as:
malignant neoplasm of breast (C50.-)
malignant neoplasm of ovary (C56.-)
Notes
Use one code, as available, for each receptor: Z17.0, Z17.1, Z17.2-, Z17.3-
Applies from Z17.4 Combined receptor status
Notes
Assign a code from subcategory Z17.4- when only a combined receptor status is documented
Applies from Z17.42 Hormone receptor negative
Applicable to
HR-
MS-DRG index
Defines the logic of DRG(s) 951 in MDC 23.
Medicare Code Edits (MCE v43.1 (April 2026))
Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.
Code annotations containing back-references to Z17.421
Back-references to Z17
Use Additional: C50 Malignant neoplasm of breast ("code to identify estrogen, and other hormones and factors receptor status (Z17.-)")
Diagnosis Index entries for Z17.421
Status (post) › combined receptor › negative › hormone receptor negative with human epidermal growth factor receptor 2 negative