Excludes1 pair
C64- vs C65-
C64 and C65 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 C64
malignant neoplasm of renal calyces (C65.-)
C64
Malignant neoplasm of kidney, except renal pelvis
Not billable
- Chapter 2
- Neoplasms
- Section
- C64-C68
Indexed under
- Nephroblastoma (epithelial) (mesenchymal)
- Nephroma
- Wilms' tumor
- Adenocarcinoma › renal cell
- Carcinoma › renal cell
C65
Malignant neoplasm of renal pelvis
Not billable
- Chapter 2
- Neoplasms
- Section
- C64-C68
Use when the record says
- malignant neoplasm of pelviureteric junction
- malignant neoplasm of renal calyces
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