I33.9 — Acute and subacute endocarditis, unspecified
I33.9 is a billable, specific ICD-10-CM code for acute and subacute endocarditis, unspecified. It is valid for submission on a claim.
Inclusion terms
Alternative wordings a physician may use in the chart for this same code.
- Acute endocarditis NOS
- Acute myoendocarditis NOS
- Acute periendocarditis NOS
- Subacute endocarditis NOS
- Subacute myoendocarditis NOS
- Subacute periendocarditis NOS
Risk adjustment
I33.9 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
I33.9 is named in 12 Medicare coverage policies — 12 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
- A56500Billing and Coding: Cardiac Catheterization and Coronary Angiography
- A56500Billing and Coding: Cardiac Catheterization and Coronary Angiography
How I33.9 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 I33.9.
- Endocarditis›acute or subacute
- Endocarditis›toxic
- Endocarditis›aortic›acute or subacute
- Endocarditis›pulmonary›acute or subacute
- Endocarditis›mitral›nonrheumatic›acute or subacute
- Endocarditis›tricuspid›nonrheumatic›acute or subacute
Related codes at this level
Codes that share I33. If I33.9 is not quite right, the correct code is usually one of these.
Questions about I33.9
- Is I33.9 a billable ICD-10-CM code?
- Yes. I33.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
- Where does I33.9 sit in the tabular list?
- Diseases of the circulatory system (I00-I99), in the block Other forms of heart disease (I30-I5A).