FY2027 ICD-10-CM reference
I33.0: Acute and subacute infective endocarditis
By the HCC Buddy Coding Team
The official ICD-10-CM descriptor is Acute and subacute infective endocarditis. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Billable code. Verified against the official FY2027 order file.
FY2027 Tabular instructions
Instructions below include applicable chapter, section and parent-code notes. Each note identifies where it appears in the official source.
Excludes2
certain conditions originating in the perinatal period (P04-P96)
Source: I00-I99 (chapter, inherited).
Excludes2
certain infectious and parasitic diseases (A00-B99)
Source: I00-I99 (chapter, inherited).
Excludes2
complications of pregnancy, childbirth and the puerperium (O00-O9A)
Source: I00-I99 (chapter, inherited).
Excludes2
congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
Source: I00-I99 (chapter, inherited).
Excludes2
endocrine, nutritional and metabolic diseases (E00-E88)
Source: I00-I99 (chapter, inherited).
Excludes2
injury, poisoning and certain other consequences of external causes (S00-T88)
Source: I00-I99 (chapter, inherited).
Excludes2
neoplasms (C00-D49)
Source: I00-I99 (chapter, inherited).
Excludes2
symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Source: I00-I99 (chapter, inherited).
Excludes2
systemic connective tissue disorders (M30-M36)
Source: I00-I99 (chapter, inherited).
Excludes2
transient cerebral ischemic attacks and related syndromes (G45.-)
Source: I00-I99 (chapter, inherited).
Excludes1
acute rheumatic endocarditis (I01.1)
Source: I33 (category, inherited).
Excludes1
endocarditis NOS (I38)
Source: I33 (category, inherited).
Instructional note
Bacterial endocarditis (acute) (subacute)
Source: I33.0 (self, direct).
Instructional note
Infective endocarditis (acute) (subacute) NOS
Source: I33.0 (self, direct).
Instructional note
Endocarditis lenta (acute) (subacute)
Source: I33.0 (self, direct).
Instructional note
Malignant endocarditis (acute) (subacute)
Source: I33.0 (self, direct).
Instructional note
Purulent endocarditis (acute) (subacute)
Source: I33.0 (self, direct).
Instructional note
Septic endocarditis (acute) (subacute)
Source: I33.0 (self, direct).
Instructional note
Ulcerative endocarditis (acute) (subacute)
Source: I33.0 (self, direct).
Instructional note
Vegetative endocarditis (acute) (subacute)
Source: I33.0 (self, direct).
Instructional note
code (B95-B97) to identify infectious agent
Source: I33.0 (self, direct).
Compare the FY2027 additions, removals and billable-status changes
What does I33.0 mean in FY2027?
The official ICD-10-CM descriptor is Acute and subacute infective endocarditis. The FY2027 annual edition starts October 1, 2026. Check the edition that applies to the encounter or inpatient discharge, including any April update.
Is I33.0 billable in FY2027?
The FY2027 order file marks I33.0 as billable. Check the complete Tabular instructions and documentation before assigning it.
Does I33.0 map to an HCC?
I33.0 has no CMS-HCC V28 category in the CMS 2027 Initial ICD-10-CM Mappings (payment year 2027, 2026 dates of service). ESRD, RxHCC, PACE and HHS-HCC mappings are still pending verification for FY2027.
Source: CMS FY2027 ICD-10-CM order file. Read the FY2027 Official Guidelines.
Review the FY2026 April edition