Excludes1 pair
I38 vs I42.4
I38 and I42.4 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 I38
endocardial fibroelastosis (I42.4)
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
I42.4
Endocardial fibroelastosis
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I30-I5A
Use when the record says
- Congenital cardiomyopathy
- Elastomyofibrosis
Indexed under
- Elastomyofibrosis
- Fibroelastosis (cordis) (endocardial) (endomyocardial)
- Cardiomyopathy › congenital
- Sclerosis, sclerotic › subendocardial, congenital
- Anomaly, anomalous › heart › fibroelastosis cordis
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