Is ICD-10-CM code I22 billable?

No, I22 (Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction) is a non-billable ICD-10-CM code. It must be coded to a more specific subcategory before it can be used for reimbursement.

What chapter does ICD-10-CM code I22 belong to?

I22 belongs to Chapter 9 of the ICD-10-CM tabular list: I00–I99 (Diseases of the Circulatory System).

I22Not billable, use a more specific code below

Subsequent ST elevation (STEMI) and non-ST elevation (NSTEMI) myocardial infarction

In Ischemic heart diseases (I20-I25), chapter 9: Diseases of the Circulatory System

5 billable codes under I22: all are an MCC; all map to HCC 228 (Acute Myocardial Infarction).A CC or MCC (major CC) is a secondary diagnosis that raises the MS-DRG payment. An HCC counts toward a Medicare Advantage patient's risk score.

Instructional notes

Includes: conditions that are coded here

acute myocardial infarction occurring within four weeks (28 days) of a previous acute myocardial infarction, regardless of site
cardiac infarction
coronary (artery) embolism
coronary (artery) occlusion
coronary (artery) rupture
coronary (artery) thrombosis
infarction of heart, myocardium, or ventricle
recurrent myocardial infarction
reinfarction of myocardium
rupture of heart, myocardium, or ventricle
subsequent type 1 myocardial infarction

Excludes1: not coded here, use a different code

subsequent myocardial infarction, type 2 (I21.A1)
subsequent myocardial infarction of other type (type 3) (type 4) (type 5) (I21.A9)

Use additional code: add a second code for this, listed after this one

code, if applicable, to identify:
exposure to environmental tobacco smoke (Z77.22)
history of tobacco dependence (Z87.891)
occupational exposure to environmental tobacco smoke (Z57.31)
status post administration of tPA (rtPA) in a different facility within the last 24 hours prior to admission to current facility (Z92.82)
tobacco dependence (F17.-)
tobacco use (Z72.0)

Also applies, from Ischemic heart diseases (I20-I25)

These notes sit on I20-I25 and apply to every code under it, including I22.

Code also: add a code for this too, order depends on the encounter

the presence of hypertension (I10-I1A)

Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Section I.C.9.e Acute myocardial infarction (AMI) (page 54), covers I22
Report I21 codes while the MI is four weeks old or less; afterward use aftercare codes, or I25.2 for old MI. Use I22 with I21 only for a new type 1 or unspecified MI within four weeks.

All codes under I22

I22 can't be used on a claim. Pick a billable code below; grey headings group them.

I22 MS-DRGs

As the principal diagnosis, all 5 billable codes under I22 group to MS-DRG 280, 281, 282, 283, 284, or 285 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Other codes that refer to I22

Notes on these codes point to I22.

I21 Excludes2: subsequent type 1 myocardial infarction (I22.-)
I25.82 Excludes1: acute coronary occlusion with myocardial infarction (I21.0-I21.B, I22.-)
Z92.82 Code First: acute myocardial infarction (I21.-, I22.-)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Heart Attack

A heart attack, also called a myocardial infarction, is a type of heart disease. It happens when blood flow to the heart suddenly becomes blocked. Without the blood coming in, the heart can't get oxygen. If not treated quickly, the heart muscle begins to die.

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.