Diseases of the circulatory system (I00–I99) ICD-10-CM
Chapter 9 of the ICD-10-CM classification spans codes I00–I99 and contains 1,798 diagnosis codes for diseases of the circulatory system, of which 1,427 are billable. The chapter is organized into 10 sections listed below, each linking to its code ranges and individual codes.
Chapter Coding Notes
Excludes2: certain conditions originating in the perinatal period (P04-P96), certain infectious and parasitic diseases (A00-B99), complications of pregnancy, childbirth and the puerperium (O00-O9A), congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99), endocrine, nutritional and metabolic diseases (E00-E88), injury, poisoning and certain other consequences of external causes (S00-T88), neoplasms (C00-D49), symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94), systemic connective tissue disorders (M30-M36), transient cerebral ischemic attacks and related syndromes (G45.-)
Sections in This Chapter 10 ranges · 1,798 codes
The info icon previews the code ranges inside each row and its instructional notations from the official Tabular List.
About Chapter 9
Chapter 9 (I00–I99) covers conditions that affect the heart, blood vessels, and overall blood circulation. These codes are used to classify diseases like heart attacks, high blood pressure, and strokes for diagnosis and treatment records.
This chapter includes a wide variety of circulatory system disorders, ranging from heart diseases such as ischemic heart disease and arrhythmias to vascular problems like hypertension and peripheral artery disease. It also encompasses cerebrovascular diseases, which involve blood flow to the brain and can lead to strokes. These codes help healthcare professionals document and manage conditions related to the heart's function, blood vessels’ health, and circulation abnormalities, facilitating appropriate medical care and monitoring of chronic cardiovascular illnesses.
Questions About This Page
How many codes are in the I00-I99 range?
The I00-I99 range contains 1,798 ICD-10-CM diagnosis codes in FY 2026. 1,427 of them are billable, and the rest are category headers that organize the chapter.
What conditions does I00-I99 cover?
The range covers diseases of the circulatory system. The sections listed above break it into groups of related conditions, and each one links to its own page with the full code list.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
