FY2027
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Excludes1 pair

I01.1 vs I33-

I01.1 and I33 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 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 (aortic) (mitral) (pulmonary) (tricuspid)
  • Endocarditis › mitral › active or acute
  • Endocarditis › rheumatic › active or acute (aortic) (mitral) (pulmonary) (tricuspid)
  • Endocarditis › tricuspid › active or acute
  • Stenosis, stenotic › mitral › active or acute
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