Is I33 a billable ICD-10-CM code?

No. I33 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does I33 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 I33?

I33 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

I33

I33 — Acute and subacute endocarditis

Non-billable headerICD-10-CM

I33 is a non-billable header ICD-10-CM code for acute and subacute endocarditis. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

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

Risk adjustment

I33 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.

Code to one of these instead I33

2 child codes. Green means billable.

Questions about I33

Is I33 a billable ICD-10-CM code?: No. I33 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does I33 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 I33?: I33 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.