Is I40.9 a billable ICD-10-CM code?

Yes. I40.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.

Where does I40.9 sit in the tabular list?

Diseases of the circulatory system (I00-I99), in the block Other forms of heart disease (I30-I5A).

What cannot be coded together with I40.9?

I40.9 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above I40.9 (I40) and apply to it just the same.

I40.9

I40.9 — Acute myocarditis, unspecified

Billable / specific codeICD-10-CM

I40.9 is a billable, specific ICD-10-CM code for acute myocarditis, unspecified. It is valid for submission on a claim.

Excludes1 inherited from the categories above I40.9

These are not written on I40.9, but they bind it: a note on a category applies to every code beneath it. Billing I40.9 with anything listed here is a denial.

Written on I40 — Acute myocarditis

acute rheumatic myocarditis (I01.2)

Other codes that can never be billed with I40.9

These codes carry an Excludes1 note pointing at I40.9. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading I40.9 alone.

I51.4Myocarditis, unspecified

Risk adjustment

I40.9 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

I40.9 is named in 11 Medicare coverage policies — 11 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
A56432Billing and Coding: Infliximab
A56500Billing and Coding: Cardiac Catheterization and Coronary Angiography

How I40.9 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 I40.9.

Myocarditis›active
Myocarditis›acute or subacute(interstitial)
Myocarditis›nonrheumatic, active
Myocarditis›parenchymatous
Rupture, ruptured›cardiac›infectional

Code history

I40.9 has not changed since FY2024 — no addition, revision or deletion across the three most recent ICD-10-CM releases.

Related codes at this level

Codes that share I40. If I40.9 is not quite right, the correct code is usually one of these.

Questions about I40.9

Is I40.9 a billable ICD-10-CM code?: Yes. I40.9 is a billable, specific ICD-10-CM code and is valid for submission on a claim.
Where does I40.9 sit in the tabular list?: Diseases of the circulatory system (I00-I99), in the block Other forms of heart disease (I30-I5A).
What cannot be coded together with I40.9?: I40.9 carries Excludes1 notes, which means the conditions they list can never be coded together with it on the same encounter. Some are written on the categories above I40.9 (I40) and apply to it just the same.