What is ICD-10 code I70.231?

I70.231 is the ICD-10-CM diagnosis code for Atherosclerosis of native arteries of right leg with ulceration of thigh. Hardening of blood vessels in the right leg with an open sore or wound on the thigh due to poor circulation. I70.231 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. I70.231 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. I70.231 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. I70.231 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for I70.231?

I70.231 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards I70.231 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting I70.231?

This code combines atherosclerosis with ulceration of the thigh; ensure both conditions are documented Document the specific location of ulceration (thigh) and confirm it is on the right leg

I70.231: Atherosclerosis of native arteries of right leg with ulceration of thigh — ICD-10

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupI70.231Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the circulatory system (I00-I99) / Diseases of arteries, arterioles and capillaries (I70-I79)

I70.231

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Atherosclerosis of native arteries of right leg with ulceration of thigh

Hardening of blood vessels in the right leg with an open sore or wound on the thigh due to poor circulation.

Buddy Insight

Atherosclerosis of native arteries with ulceration indicates severe peripheral arterial disease (Fontaine Stage IV/Rutherford Category 5) where impaired blood flow has caused tissue breakdown.

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 311

Diabetic and Chronic Skin Ulcer

RAF 0.0

Code Trumping

Basket needed

Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

I70.2Atherosclerosis of native arteries of the extremities

I70.23Atherosclerosis of native arteries of right leg with ulceration

I70.231Atherosclerosis of native arteries of right leg with ulceration of thigh

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for I70.231 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for I70.231 in this effective period.

Related Child Codes

Official

I70.232Atherosclerosis of native arteries of right leg with ulceration of calf

I70.233Atherosclerosis of native arteries of right leg with ulceration of ankle

I70.234Atherosclerosis of native arteries of right leg with ulceration of heel and midfoot

I70.235Atherosclerosis of native arteries of right leg with ulceration of other part of foot

I70.238Atherosclerosis of native arteries of right leg with ulceration of other part of lower leg

Includes

Official

any condition classifiable to I70.211 and I70.221
chronic limb-threatening ischemia of native arteries of right leg with ulceration
critical limb ischemia of native arteries of right leg with ulceration

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for I70.231 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for I70.231 in this effective period.

Use Additional

Official

code to identify severity of ulcer (L97.-)

Code Also

Official

ICD-10-CM does not list Code Also instructions for I70.231 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Clinical diagnosis of peripheral atherosclerosis explicitly documented by the provider

Specification of the affected vessel type (native arteries)

Laterality clearly documented (right leg)

Documentation of the ulcer location (thigh) with description of size, depth, and wound characteristics

MEAT Support

HCC Buddy guidance

Clinical diagnosis of peripheral atherosclerosis explicitly documented by the provider

Specification of the affected vessel type (native arteries)

Laterality clearly documented (right leg)

Documentation of the ulcer location (thigh) with description of size, depth, and wound characteristics

Audit Caution

HCC Buddy guidance

Coding bypass graft atherosclerosis codes (I70.3xx-I70.7xx) when the disease is in native arteries — verify whether the patient has a history of bypass graft surgery before selecting the code category

Failing to document the specific ulcer site (thigh) — the code requires specificity of the anatomic location of the ulcer

Coding a venous stasis ulcer or diabetic neuropathic ulcer as an atherosclerotic arterial ulcer — the etiology must be confirmed as arterial insufficiency from atherosclerosis

Not assigning an additional code from L97 or L98 to identify the ulcer severity (depth and tissue involvement) when applicable

Common Mistakes

HCC Buddy guidance

I70.3xx (bypass graft series) — Use I70.3xx when atherosclerosis involves a bypass graft rather than native arteries; the graft type must be specified when known

I70.221-I70.229 (native arteries with rest pain) — Use rest pain codes only when there is no ulceration or gangrene present; ulceration codes include the rest pain component

L97.x (Non-pressure chronic ulcer of lower limb) — L97 codes describe ulcers not specified as due to atherosclerosis; use I70.23x-I70.25 when the ulcer is clearly arterial in etiology. An additional L97 code may be assigned for ulcer severity

I70.261-I70.269 (native arteries with gangrene) — If gangrene is present along with ulceration, code the gangrene category as it represents greater severity

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is I70.231 an HCC code?

No. I70.231 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

RxHCCHCC 311, Diabetic and Chronic Skin Ulcer

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

Work I70.231 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for I70.231

For I70.231to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically, it has to be re-documented and supported each calendar year.

MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
EEvaluate: test results, medication response, or physical findings reviewed by the provider
AAssess: explicit mention in the assessment or plan with acknowledgment of status
TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis

Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed I70.231 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

Get the V28 RAF + MEAT cheat sheet

One printable page: confirm a code's V28 HCC status, its RAF weight, and the MEAT your note needs to make it stick. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

I70.231 is the ICD-10-CM diagnosis code for atherosclerosis of native arteries of right leg with ulceration of thigh. Hardening of blood vessels in the right leg with an open sore or wound on the thigh due to poor circulation. I70.231 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering diseases of arteries, arterioles and capillaries (i70-i79).

I70.231 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

This code does not map to an HCC under the CMS-HCC V28 model. It does not map to an HCC under the CMS-HCC V24 model. It does not map to an HCC under the ESRD model. In the RxHCC model, it maps to RxHCC 311 but carries a RAF weight of 0.0, meaning it is recognized for prescription drug risk adjustment but does not independently increase the RAF score. While these ulceration codes do not map to CMS-HCC V24 or V28 directly, they are recognized in the RxHCC model. The ulceration indicates significant disease severity that should be captured for complete clinical documentation even when HCC impact is limited.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for I70.231 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This code combines atherosclerosis with ulceration of the thigh; ensure both conditions are documented
•Document the specific location of ulceration (thigh) and confirm it is on the right leg

Clinical Significance

Atherosclerosis of native arteries with ulceration indicates severe peripheral arterial disease (Fontaine Stage IV/Rutherford Category 5) where impaired blood flow has caused tissue breakdown. These arterial ulcers require specialized wound care, vascular assessment, and often revascularization to promote healing and prevent amputation. This combination code captures both the underlying vascular disease and the ulcerative complication, reflecting the increased care complexity and resource needs.

Documentation Requirements

✓Clinical diagnosis of peripheral atherosclerosis explicitly documented by the provider
✓Specification of the affected vessel type (native arteries)
✓Laterality clearly documented (right leg)
✓Documentation of the ulcer location (thigh) with description of size, depth, and wound characteristics
✓Confirmation that the ulcer is arterial in etiology (as opposed to venous, diabetic neuropathic, or pressure ulcer)
✓Wound assessment details including wound bed description, drainage, presence of infection, and staging if applicable
✓Vascular assessment findings (ankle-brachial index, pulse examination, or arterial Doppler studies) supporting ischemic etiology
✓Current wound care and vascular treatment plan

Commonly Confused Codes

•I70.3xx (bypass graft series): Use I70.3xx when atherosclerosis involves a bypass graft rather than native arteries; the graft type must be specified when known
•I70.221-I70.229 (native arteries with rest pain): Use rest pain codes only when there is no ulceration or gangrene present; ulceration codes include the rest pain component
•L97.x (Non-pressure chronic ulcer of lower limb): L97 codes describe ulcers not specified as due to atherosclerosis; use I70.23x-I70.25 when the ulcer is clearly arterial in etiology. An additional L97 code may be assigned for ulcer severity
•I70.261-I70.269 (native arteries with gangrene): If gangrene is present along with ulceration, code the gangrene category as it represents greater severity
•E11.621 (Type 2 diabetes mellitus with foot ulcer): Diabetic foot ulcers are coded differently; if both atherosclerosis and diabetes contribute, both conditions should be coded