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I33.0

I33.0Acute and subacute infective endocarditis

Billable / specific codeICD-10-CM

I33.0 is a billable, specific ICD-10-CM code for acute and subacute infective endocarditis. It is valid for submission on a claim.

Use additional code

Add a secondary code to capture the detail described below.

  • code (B95-B97) to identify infectious agent

Inclusion terms

Alternative wordings a physician may use in the chart for this same code.

  • Bacterial endocarditis (acute) (subacute)
  • Infective endocarditis (acute) (subacute) NOS
  • Endocarditis lenta (acute) (subacute)
  • Malignant endocarditis (acute) (subacute)
  • Purulent endocarditis (acute) (subacute)
  • Septic endocarditis (acute) (subacute)
  • Ulcerative endocarditis (acute) (subacute)
  • Vegetative endocarditis (acute) (subacute)

Risk adjustment

I33.0 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Medicare coverage

I33.0 is named in 26 Medicare coverage policies 26 listing it as supporting medical necessity. Which of them applies to you depends on your Medicare contractor, and coverage genuinely differs by state.

  • A52850Billing and Coding: Cardiac Catheterization and Coronary Angiography
  • A52850Billing and Coding: Cardiac Catheterization and Coronary Angiography
  • A52868Billing and Coding: Transesophageal Echocardiography (TEE)
  • A52868Billing and Coding: Transesophageal Echocardiography (TEE)

How I33.0 is indexed

Coders do not find codes by browsing the tabular list — they look them up in the alphabetic index, under the word the physician wrote. These are the index entries that lead here, so you can see which chart wordings map to I33.0.

  • Osler's nodes
  • SBE(subacute bacterial endocarditis)
  • Aneurysmendocardial, infective(any valve)
  • Endocarditisbacterial(acute) (any valve) (subacute)
  • Endocarditisconstrictive
  • Endocarditisinfectious or infective(acute) (any valve) (subacute)
  • Endocarditislenta(acute) (any valve) (subacute)
  • Endocarditismalignant(acute) (any valve) (subacute)
  • Endocarditismycotic(acute) (any valve) (subacute)
  • Endocarditispneumococcal(acute) (any valve) (subacute)
  • Endocarditispurulent(acute) (any valve) (subacute)
  • Endocarditisseptic(acute) (any valve) (subacute)

Related codes at this level

Codes that share I33. If I33.0 is not quite right, the correct code is usually one of these.

Questions about I33.0

Is I33.0 a billable ICD-10-CM code?
Yes. I33.0 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does I33.0 sit in the tabular list?
Diseases of the circulatory system (I00-I99), in the block Other forms of heart disease (I30-I5A).
ICD-10-CMFY2026-Apr· effective April 1, 2026

Loaded directly from the CMS/NCHS ICD-10-CM public-domain release — see data sources and our editorial policy. If this page disagrees with the CMS tabular list, this page is wrong. Reference information for professional coders; not medical or billing advice.