Excludes1 pair
I09.1 vs I38
I09.1 and I38 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 I09.1
endocarditis, valve unspecified (I38)
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
I38
Endocarditis, valve unspecified
BillableUnspecified
- Chapter 9
- Diseases of the circulatory system
- Section
- I30-I5A
Use when the record says
- endocarditis (chronic) NOS
- valvular incompetence NOS
- valvular insufficiency NOS
- valvular regurgitation NOS
- valvular stenosis NOS
- valvulitis (chronic) NOS
Indexed under
- Endocarditis (chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
- Disease, diseased › valve, valvular
- Endocarditis › arteriosclerotic
- Insufficiency, insufficient › valve, valvular (heart)
- Stenosis, stenotic › heart valve
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