Is ICD-10-CM code I25 billable?

No, I25 (Chronic ischemic heart disease) 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 I25 belong to?

I25 belongs to Chapter 9 of the ICD-10-CM tabular list: I00–I99 (Diseases of the Circulatory System).

I25Not billable, use a more specific code below

Chronic ischemic heart disease

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

56 billable codes under I25: 1 is an MCC, 38 are a CC; 8 map to HCC 229 (Unstable Angina and Other Acute Ischemic Heart Disease).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

Excludes2: not included here, code separately if applicable

non-ischemic myocardial injury (I5A)

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

code to identify:
chronic total occlusion of coronary artery (I25.82)
exposure to environmental tobacco smoke (Z77.22)
history of tobacco dependence (Z87.891)
occupational exposure to environmental tobacco smoke (Z57.31)
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 I25.

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.

Covers hypertension with heart and kidney disease, coronary artery disease with angina, perioperative stroke, cerebrovascular sequelae, and acute myocardial infarction types and timing.

Hypertension (page 50)
Atherosclerotic Coronary Artery Disease and Angina (page 52)
Intraoperative and Postprocedural Cerebrovascular Accident (page 53)
Sequelae of Cerebrovascular Disease (page 53)
Acute myocardial infarction (AMI) (page 54)

Read Section I.C.9 (page 50)

All codes under I25

I25 can't be used on a claim. Pick a billable code below; grey headings group them.

I25 MS-DRGs

As the principal diagnosis, the billable codes under I25 group to these 7 MS-DRGs (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

DRG 302 Atherosclerosis with MCC (53 of 56 codes)
DRG 303 Atherosclerosis without MCC (53 of 56 codes)
DRG 314 Other Circulatory System Diagnoses with MCC (3 of 56 codes)
DRG 315 Other Circulatory System Diagnoses with CC (3 of 56 codes)
DRG 316 Other Circulatory System Diagnoses without CC/MCC (3 of 56 codes)
DRG 791 Prematurity with Major Problems (1 of 56 codes)
DRG 793 Full Term Neonate with Major Problems (1 of 56 codes)

Other codes that refer to I25

Notes on these codes point to I25.

I74 Excludes2: coronary embolism and thrombosis (I21-I25)
I82 Excludes2: coronary (I21-I25)

About the condition

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

Atherosclerosis

Atherosclerosis is a condition in which plaque builds up inside your arteries. Plaque is a sticky substance made up of cholesterol, fat, blood cells, calcium, and other substances found in the blood. Over time, plaque hardens and causes your arteries to narrow. That limits the flow of oxygen-rich blood to your body.

Coronary Artery Disease

Coronary artery disease (CAD) is the most common type of heart disease in the United States and a leading cause of death for both men and women. CAD affects the coronary arteries, which are the blood vessels that carry blood and oxygen to your heart muscle. When these arteries are damaged or diseased, your heart does not get the blood it needs.

Code history

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