C94.0 vs D64.4
C94.0 and D64.4 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on D64.4
Di Guglielmo's disease (C94.0)
C94.0
Acute erythroid leukemia
Not billable
- Chapter 2
- Neoplasms
- Section
- C81-C96
Use when the record says
- Acute myeloid leukemia M6(a)(b)
- Erythroleukemia
Indexed under
- Di Guglielmo's disease
- Erythremia (acute)
- Erythroleukemia
- Leukemia, leukemic › acute erythroid
- Myelosis › erythremic
D64.4
Congenital dyserythropoietic anemia
Billable
- Chapter 3
- Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Section
- D60-D64
Use when the record says
- Dyshematopoietic anemia (congenital)
Indexed under
- Anemia › dyserythropoietic (essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
- Anemia › dyshematopoietic (essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
- Anemia › congenital › dyserythropoietic, dyshematopoietic (essential) (general) (hemoglobin deficiency) (infantile) (primary) (profound)
These two codes sit in different chapters of the Tabular List, which is usually the clearest signal that they describe different underlying processes rather than different degrees of the same one.
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