I33 vs I38
I33 (Acute and subacute endocarditis) compared with I38 (Endocarditis, valve unspecified), from the official CMS tabular data. Do not report these codes together: the official tabular list marks them Excludes1.
Can these codes be reported together?
No — do not report together. I33 carries an Excludes1 note covering I38: “endocarditis NOS (I38)”
Sole exception: when the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).
Side by side
| I33Acute and subacute endocarditis | I38Endocarditis, valve unspecified | |
|---|---|---|
| Billing status | Non-billable header | Billable |
| Classification | I00-I99 — Diseases of the Circulatory System (I00-I99) | I00-I99 — Diseases of the Circulatory System (I00-I99) |
| Definition | Acute and subacute endocarditis is a non-billable ICD-10-CM category code (I33). | Endocarditis, valve unspecified is a billable ICD-10-CM diagnosis code (I38). |
| Includes | — | endocarditis (chronic) NOS valvular incompetence NOS valvular insufficiency NOS valvular regurgitation NOS |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources