I33

Non-billable

Acute and subacute endocarditis

I33 is the ICD-10-CM code for Acute and subacute endocarditis. It is a non-billable category code — use a more specific child code such as I33.0 for billing.

Status
Header (non-billable)
Chapter
I00-I99
Subcodes
2
Edition
FY2026

I00-I99 Diseases of the circulatory system

What this means — in plain language

MedlinePlus · NIH

What is endocarditis? Endocarditis is sometimes called infective endocarditis. It's a rare but life-threatening inflammation of the lining inside your heart's chambers and valves (the endocardium). Endocarditis is usually caused by germs that get into your bloodstream and travel to your heart. Once they get inside your heart, the germs can attach to the lining or get trapped in the valves. They start to grow,…

Read more about Endocarditis at MedlinePlus ↗

Source: U.S. National Library of Medicine (MedlinePlus). Informational only — not medical advice.

Excludes1 — not coded here

  • acute rheumatic endocarditis (I01.1)
  • endocarditis NOS (I38)

Medications indicated for this condition

FDA labeling

Drugs whose FDA labeling lists this condition's category among its indications. Informational only — not a treatment recommendation or medical advice.

Frequently asked questions

What is ICD-10 code I33?
I33 is the ICD-10-CM code for "Acute and subacute endocarditis". It falls under I00-I99 Diseases of the circulatory system.
Is I33 a billable code?
No — I33 is a non-billable header code. Use a more specific child code (such as I33.0) for billing.
What are the subcodes of I33?
I33 has 2 more specific child codes, including I33.0, I33.9.
What is excluded from I33?
Excludes1 (not coded here): acute rheumatic endocarditis (I01.1); endocarditis NOS (I38).

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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