Non-Billable / Non-Specific Code
ICD-10-CM C79 is the diagnosis code for Secondary malignant neoplasm of other and unspecified sites. This code falls under the section "Malignant neoplasms of ill-defined, other secondary and unspecified sites" within Chapter 2 — Neoplasms (C00-D49). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as C79. They are mutually exclusive:
Understanding where C79 sits in the ICD-10-CM classification helps ensure proper coding:
No, C79 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
C79 is the ICD-10-CM diagnosis code for "Secondary malignant neoplasm of other and unspecified sites". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
C79 is located in Section C76-C80 — "Malignant neoplasms of ill-defined, other secondary and unspecified sites" within Chapter 2 of the ICD-10-CM Tabular List.
C79 has 10 sub-code(s) that provide more specific detail: C79.0, C79.1, C79.2, C79.3, C79.4 and more.
Use C79 when the patients documented diagnosis matches "Secondary malignant neoplasm of other and unspecified sites" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Secondary malignant neoplasm of other and unspecified sites is C79.
No, C79 is non-billable. Use a more specific sub-code for primary diagnosis billing.
C79 is in Chapter 2 of the ICD-10-CM Tabular List.
Type 1 Excludes for C79 include: secondary carcinoid tumors (C7B.-); secondary neuroendocrine tumors (C7B.-).
Yes, C79 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.