Is C79.81 a billable ICD-10-CM code?

Yes. C79.81 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does C79.81 sit in the tabular list?

Neoplasms (C00-D49), in the block Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80).

What cannot be coded together with C79.81?

C79.81 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above C79.81 (C79) and apply to it just the same.

C79.81

C79.81 — Secondary malignant neoplasm of breast

Billable / specific codeICD-10-CM

C79.81 is a billable, specific ICD-10-CM code for secondary malignant neoplasm of breast. It is valid for submission on a claim.

Excludes1 inherited from the categories above C79.81

These are not written on C79.81, but they bind it: a note on a category applies to every code beneath it. Billing C79.81 with anything listed here is a denial.

Written on C79 — Secondary malignant neoplasm of other and unspecified sites

secondary carcinoid tumors (C7B.-)
secondary neuroendocrine tumors (C7B.-)

Risk adjustment

C79.81 risk-adjusts. Under the CMS-HCC V28 model it maps to this category:

HCC 18 Cancer Metastatic to Bone, Other and Unspecified Metastatic Cancer; Acute Leukemia Except Myeloid2.341 RAF

Coefficient shown for the Community Non-dual Aged segment. A higher HCC in the same hierarchy will suppress this one, so capturing it does not always add score.

Medicare coverage

C79.81 is named in 58 Medicare coverage policies — 58 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

A52478External Breast Prostheses - Policy Article
A52480Oral Antiemetic Drugs (Replacement for Intravenous Antiemetics) - Policy Article
A52849Billing and Coding: Breast Imaging: Breast Echography (Sonography)/Breast MRI/Ductography
A53101Billing and Coding: MolDX: bioTheranostics Cancer TYPE ID® Update

How C79.81 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to C79.81.

Melanoma›metastatic›breast

Code history

C79.81 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share C79.8. If C79.81 is not quite right, the correct code is usually one of these.

Questions about C79.81

Is C79.81 a billable ICD-10-CM code?: Yes. C79.81 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does C79.81 sit in the tabular list?: Neoplasms (C00-D49), in the block Malignant neoplasms of ill-defined, other secondary and unspecified sites (C76-C80).
What cannot be coded together with C79.81?: C79.81 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above C79.81 (C79) and apply to it just the same.