Excludes1 pair
I08- vs I09.1
I08 and I09.1 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 I08
rheumatic valve disease NOS (I09.1)
I08
Multiple valve diseases
Not billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I05-I09
Use when the record says
- multiple valve diseases specified as rheumatic or unspecified
I09.1
Rheumatic diseases of endocardium, valve unspecified
BillableUnspecified
- Chapter 9
- Diseases of the circulatory system
- Section
- I05-I09
Use when the record says
- Rheumatic endocarditis (chronic)
- Rheumatic valvulitis (chronic)
Indexed under
- Endocarditis › rheumatic (chronic) (inactive) (with chorea)
- Endocarditis › with rheumatic fever › inactive or quiescent (with chorea)
- Fever › rheumatic › inactive or quiescent with › endocarditis
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