D45 vs D75.0
D45 and D75.0 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 D45
familial polycythemia (D75.0)
D45
Polycythemia vera
Billable
- Chapter 2
- Neoplasms
- Section
- D37-D48
Indexed under
- Heilmeyer-Schoner disease
- Erythremia › chronic (acute)
- Polycythemia › vera (secondary)
D75.0
Familial erythrocytosis
Billable
- Chapter 3
- Diseases of the blood and blood-forming organs and certain disorders involving the immune mechanism
- Section
- D70-D77
Use when the record says
- Benign polycythemia
- Familial polycythemia
Indexed under
- Erythrocytosis › familial (megalosplenic) (secondary)
- Polycythemia › benign (secondary)
- Polycythemia › familial (secondary)
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