I01.1 vs I33
I01.1 and I33 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.
The official note, declared on I33
acute rheumatic endocarditis (I01.1)
I01.1
Acute rheumatic endocarditis
Billable
- Chapter 9
- Diseases of the circulatory system
- Section
- I00-I02
Use when the record says
- Any condition in I00 with endocarditis or valvulitis
- Acute rheumatic valvulitis
Indexed under
- Endocarditis › acute or subacute › rheumatic (chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
- Endocarditis › mitral › active or acute (chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
- Endocarditis › rheumatic › active or acute (chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
- Endocarditis › tricuspid › active or acute (chronic) (marantic) (nonbacterial) (thrombotic) (valvular)
- Stenosis, stenotic › mitral › active or acute (cicatricial)
I33
Acute and subacute endocarditis
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