C80.1 — Malignant (primary) neoplasm, unspecified
Is C80.1 billable?
Yes, but C80.1 is an unspecified code. C80.1 is a valid, billable ICD-10-CM code for encounters from October 1, 2026 through September 30, 2027. However, C80.1 is an unspecified or catch-all code. Payers apply additional scrutiny to unspecified codes and many deny them when the medical record supports a more specific option, so check the documentation before selecting C80.1 — the more specific alternatives are listed below.
More specific alternatives
C80.1 at a glance
| Code | C80.1 |
|---|---|
| Description | Malignant (primary) neoplasm, unspecified |
| Billable | Yes |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Which MS-DRGs does C80.1 group to?
C80.1 sits in MDC 17 and helps define the logic of 3 MS-DRGs (version 44, FY2027). Which one a stay actually groups to also depends on procedures and secondary diagnoses.
- 826Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with MCCsurgical
- 827Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures with CCsurgical
- 828Myeloproliferative Disorders or Poorly Differentiated Neoplasms with Major O.R. Procedures without CC/MCCsurgical
How is C80.1 listed in the Alphabetic Index?
These are the routes through the Alphabetic Index that lead to C80.1. They show the wording a clinician may have documented, which often differs from the Tabular description.
- Cancer › unspecified site
- Carcinoma › unspecified site (malignant)
- Malignancy › unspecified site
- Sarcomatosis › unspecified site
- Tumor › malignant
- Tumor › malignant › fusiform cell
- Tumor › malignant › giant cell
- Tumor › malignant › mixed NEC
- Tumor › malignant › small cell
- Tumor › malignant › spindle cell
- Tumor › malignant › unclassified
Excludes1 — never code together
The conditions below can never be reported together with C80.1 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- secondary malignant neoplasm of unspecified site (C79.9)
Inclusion terms
Alternative wording in documentation that is classified to C80.1.
- Cancer NOS
- Cancer unspecified site (primary)
- Carcinoma unspecified site (primary)
- Malignancy unspecified site (primary)
Excludes1 — never code together — inherited from C80
The conditions below can never be reported together with C80.1 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.
- malignant carcinoid tumor of unspecified site (C7A.00)
- malignant neoplasm of specified multiple sites- code to each site
How long has C80.1 existed?
C80.1 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
Which codes are confused with C80.1?
ICD-10-CM declares these codes mutually exclusive with C80.1 — exactly one of each pair can be correct for a given encounter.