Acute and subacute endocarditis (I33) ICD-10-CM
The I33 code range covers acute and subacute endocarditis with 3 ICD-10-CM diagnosis codes. 2 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 1 Excludes
A type 1 excludes note is a pure excludes note. It means "NOT CODED HERE!" An Excludes1 note indicates that the code excluded should never be used at the same time as the code above the Excludes1 note. An Excludes1 is used when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition.
Codes in the I33 Range 3 codes · 2 billable
About the I33 Code Range
Acute and subacute endocarditis appears under other forms of heart disease in the circulatory system chapter.
The subdivisions distinguish I33.0, for infective endocarditis, from I33.9, for endocarditis whose type is unspecified. Neither subdivision separates acute from subacute endocarditis.
Questions About This Page
How many billable codes are in the I33 range?
Of the 3 codes in this range, 2 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the I33 range classify?
The range classifies acute and subacute endocarditis. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
