2026 ICD-10-CM Diagnosis Code I70.203Unspecified atherosclerosis of native arteries of extremities, bilateral legs

ICD-10-CM Codes›I00–I99›I70-I79›I70

ICD-10-CM I70.203
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

I70.203 is a billable ICD-10-CM diagnosis code for unspecified atherosclerosis of native arteries of extremities, bilateral legs. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 299 through 301. The code is restricted by the Medicare Code Editor to adult patients (age 15 through 124). Coders also document this condition as bilateral atherosclerosis of arteries of lower limbs. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Peripheral and visceral vascular disease.

Code Identity

ICD-10-CM Code
I70.203
Billable Status
Yes — Valid for Submission
Code Describes
Unspecified atherosclerosis of native arteries of extremities, bilateral legs
Short Description
Unsp athscl native arteries of extremities, bilateral legs
Parent Code
I70.20
Unspecified atherosclerosis of native arteries of extremities

Code Classification

ChapterI00–I99Diseases of the circulatory system
SectionI70-I79Diseases of arteries, arterioles and capillaries
CategoryI70Atherosclerosis
This CodeI70.203Unspecified atherosclerosis of native arteries of extremities, bilateral legs

Code EditsBilling

Medicare Code Editor checks that affect claim validity for I70.203.

Adult diagnoses
The Medicare Code Editor detects inconsistencies in adult cases by checking a patient's age and any diagnosis on the patient's record. The adult code edits apply to patients age range is 15–124 years inclusive (e.g., senile delirium, mature cataract).

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Bilateral atherosclerosis of arteries of lower limbs
  • Stenosis of artery of bilateral lower limbs
  • Stenosis of artery of left lower limb
  • Stenosis of artery of right lower limb
  • Stenosis of lower limb artery

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Arteriosclerosis, arteriosclerotic(diffuse) (obliterans) (of) (senile) (with calcification)
      • extremities (native arteries)
        • leg
          • bilateral

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR CIR026
Peripheral and visceral vascular disease
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

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.

The full article covers:

  • What is atherosclerosis?
  • What causes atherosclerosis?
  • Who is more likely to develop atherosclerosis?
  • What are the symptoms of atherosclerosis?
  • What other problems can atherosclerosis cause?
  • How is atherosclerosis diagnosed?
  • What are the treatments for atherosclerosis?
  • Can atherosclerosis be prevented?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert I70.203 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
440.20 Athscl extrm ntv art NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About I70.203Overview

Is I70.203 a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report unspecified atherosclerosis of native arteries of extremities, bilateral legs on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does I70.203 group to?

When unspecified atherosclerosis of native arteries of extremities, bilateral legs is the principal diagnosis on an inpatient stay, it groups to MS-DRG 299, 300, 301, with relative weights from 0.7197 to 1.6327 depending on complications. Higher weights mean higher Medicare reimbursement.

Who can I70.203 be reported for?

The Medicare Code Editor checks unspecified atherosclerosis of native arteries of extremities, bilateral legs against patient demographics: this code is intended for adult patients (age 15 through 124). Claims outside these limits are flagged as inconsistent.

What is the ICD-9 equivalent of I70.203?

Under the General Equivalence Mappings, unspecified atherosclerosis of native arteries of extremities, bilateral legs converts to ICD-9-CM 440.20 (athscl extrm ntv art NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.