Excludes1 pair
I70- vs I77.6
I70 and I77.6 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 I77.6
deformans (I70.-)
I70
Atherosclerosis
Not billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I70-I79
Use when the record says
- arteriolosclerosis
- arterial degeneration
- arteriosclerosis
- arteriosclerotic vascular disease
- arteriovascular degeneration
- atheroma
- endarteritis deformans or obliterans
- senile arteritis
I77.6
Arteritis, unspecified
BillableUnspecified
- Chapter 9
- Diseases of the circulatory system
- Section
- I70-I79
Use when the record says
- Aortitis NOS
- Endarteritis NOS
Indexed under
- Angiitis
- Aortitis (nonsyphilitic) (calcific)
- Arteriolitis
- Arteritis
- Endarteritis (bacterial, subacute) (infective)
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