G10 vs G25.5
G10 and G25.5 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 G25.5
Huntington's chorea (G10)
G10
Huntington's disease
Billable
- Chapter 6
- Diseases of the nervous system
- Section
- G10-G14
Use when the record says
- Huntington's chorea
- Huntington's dementia
Indexed under
- Huntington's disease or chorea
- Chorea › hereditary (chronic) (gravis) (posthemiplegic) (senile) (spasmodic)
- Chorea › Huntington's (chronic) (gravis) (posthemiplegic) (senile) (spasmodic)
- Disease, diseased › Huntington's
- Huntington's disease or chorea › with dementia
G25.5
Other chorea
Billable
- Chapter 6
- Diseases of the nervous system
- Section
- G20-G26
Use when the record says
- Chorea NOS
Indexed under
- Chorea (chronic) (gravis) (posthemiplegic) (senile) (spasmodic)
- Choreoathetosis (paroxysmal)
- Hemiballism (us)
- Hemichorea
- Chorea › progressive (chronic) (gravis) (posthemiplegic) (senile) (spasmodic)
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