Excludes1 pair
G30- vs G31.1
G30 and G31.1 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 G30
senile degeneration of brain NEC (G31.1)
G30
Alzheimer's disease
Not billable
- Chapter 6
- Diseases of the nervous system
- Section
- G30-G32
Use when the record says
- Alzheimer's dementia senile and presenile forms
G31.1
Senile degeneration of brain, not elsewhere classified
BillableUnspecified
- Chapter 6
- Diseases of the nervous system
- Section
- G30-G32
Indexed under
- Degeneration, degenerative › motor centers, senile
- Atrophy, atrophic › brain › senile NEC
- Degeneration, degenerative › brain › senile NEC
- Degeneration, degenerative › senile › brain
- Degeneration, degenerative › senile › motor centers
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