I33 – Acute and subacute endocarditis

ICD-10-CM 2027 diagnosis code · Other forms of heart disease

Non-billable header

ICD-10-CM code I33
Code
I33 (claims format: I33)
Description
Acute and subacute endocarditis
Billable
No – use a more specific code below
Valid for
Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter
9. Diseases of the circulatory system (I00-I99)
Block
I30-I5A Other forms of heart disease

Billable codes under I33

I33 is a header code and cannot be used on claims. Choose the most specific code:

Notes for I33

Excludes1 (not coded here):
  • acute rheumatic endocarditis (I01.1)
  • endocarditis NOS (I38)

Frequently asked questions

What is ICD-10 code I33?

I33 is the ICD-10-CM code for acute and subacute endocarditis, in the block I30-I5A (Other forms of heart disease).

Is I33 a billable code?

No. I33 is a header code with more specific child codes; report one of the billable codes listed above.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.