FY2027
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Excludes1 pair

C76- vs C80.1

C76 and C80.1 are not coded together. ICD-10-CM declares them mutually exclusive with an Excludes1 note — the two conditions are not expected to occur together, so exactly one of them is normally correct for a given encounter. The Official Guidelines carve out one exception: if the two conditions are clearly unrelated to each other, both may be reported.

The official note, declared on C76
malignant neoplasm of unspecified site NOS (C80.1)
C76

Malignant neoplasm of other and ill-defined sites

Not billable
Chapter 2
Neoplasms
Section
C76-C80
C80.1

Malignant (primary) neoplasm, unspecified

BillableUnspecified
Chapter 2
Neoplasms
Section
C76-C80
Use when the record says
  • Cancer NOS
  • Cancer unspecified site (primary)
  • Carcinoma unspecified site (primary)
  • Malignancy unspecified site (primary)
Indexed under
  • Cancer › unspecified site (primary)
  • Carcinoma › unspecified site (primary)
  • Malignancy › unspecified site (primary)
  • Sarcomatosis › unspecified site
  • Tumor › malignant

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027