Excludes1 pair
I05.9 vs I34-
I05.9 and I34 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 I34
mitral valve disease (I05.9)
I05.9
Rheumatic mitral valve disease, unspecified
BillableUnspecified
- Chapter 9
- Diseases of the circulatory system
- Section
- I05-I09
Use when the record says
- Rheumatic mitral (valve) disorder (chronic) NOS
Indexed under
- Disease, diseased › mitral (valve)
- Endocarditis › mitral (chronic) (double) (fibroid) (heart) (inactive) (valve) (with chorea)
- Lesion › mitral
- Disease, diseased › heart › mitral
- Endocarditis › mitral › with › rheumatic fever › inactive or quiescent (with chorea)
I34
Nonrheumatic mitral valve disorders
Not billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I30-I5A
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