Excludes1 pair
G10 vs G25.5
G10 and G25.5 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 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
- Chorea › Huntington's
- 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
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