What is ICD-10 code L97.304?

L97.304 is the ICD-10-CM diagnosis code for Non-pressure chronic ulcer of unspecified ankle with necrosis of bone. A long-lasting open sore on the ankle (not from pressure) where the bone tissue has died and deteriorated. L97.304 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. L97.304 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. L97.304 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. L97.304 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 L97.304?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For L97.304, V28 maps to Chronic Ulcer of Skin, Except Pressure at RAF 0.426 while V24 mapped to Chronic Ulcer of Skin, Except Pressure at RAF 0.426. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting L97.304?

Bone necrosis is the most severe non-pressure ulcer category; requires imaging confirmation (X-ray or MRI) documented in the record This indicates osteomyelitis risk; coordinate with infectious disease documentation if applicable Because L97.304 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

L97.304 ICD-10 Code: Non-pressure chronic ulcer

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 lookupL97.304Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the skin and subcutaneous tissue (L00-L99) / Other disorders of the skin and subcutaneous tissue (L80-L99)

L97.304

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

Non-pressure chronic ulcer of unspecified ankle with necrosis of bone

A long-lasting open sore on the ankle (not from pressure) where the bone tissue has died and deteriorated.

Buddy Insight

Non-pressure chronic ulcers of the lower extremity are significant indicators of underlying vascular disease, diabetes, or other systemic conditions that impair wound healing.

CMS-HCC V28

Mapped

HCC 380

Chronic Ulcer of Skin, Except...

RAF 0.426

CMS-HCC V24

Mapped

HCC 161

Chronic Ulcer of Skin, Except...

RAF 0.426

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 161

Chronic Ulcer of Skin, Except...

RAF 0.0

RXHCC

Mapped

HCC 311

Diabetic and Chronic Skin Ulcer

RAF 0.0

Code Trumping

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Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

L97.3Non-pressure chronic ulcer of ankle

L97.30Non-pressure chronic ulcer of unspecified ankle

L97.304Non-pressure chronic ulcer of unspecified ankle with necrosis of bone

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for L97.304 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for L97.304 in this effective period.

Related Child Codes

Official

L97.301Non-pressure chronic ulcer of unspecified ankle limited to breakdown of skin

L97.302Non-pressure chronic ulcer of unspecified ankle with fat layer exposed

L97.303Non-pressure chronic ulcer of unspecified ankle with necrosis of muscle

L97.305Non-pressure chronic ulcer of unspecified ankle with muscle involvement without evidence of necrosis

L97.306Non-pressure chronic ulcer of unspecified ankle with bone involvement without evidence of necrosis

Includes

Official

ICD-10-CM does not list Includes notes for L97.304 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for L97.304 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for L97.304 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for L97.304 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for L97.304 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Ulcer site documented as unspecified ankle with clear laterality (unspecified side)

Confirmation that the ulcer is chronic (present for extended duration, not acute)

Etiology documented as non-pressure (e.g., venous stasis, arterial insufficiency, diabetic, or other non-pressure cause)

Clinical assessment of wound depth and tissue involvement

MEAT Support

HCC Buddy guidance

Ulcer site documented as unspecified ankle with clear laterality (unspecified side)

Confirmation that the ulcer is chronic (present for extended duration, not acute)

Etiology documented as non-pressure (e.g., venous stasis, arterial insufficiency, diabetic, or other non-pressure cause)

Clinical assessment of wound depth and tissue involvement

Audit Caution

HCC Buddy guidance

Failing to verify laterality — documentation must specify unspecified ankle; do not assume based on previous encounters

Coding a pressure ulcer code (L89.-) when the ulcer is actually non-pressure in etiology (venous, arterial, diabetic)

Coding bone necrosis without imaging or clinical confirmation — provider must document necrotic bone, not just bone exposure

Confusing 7th character 4 (necrosis of bone) with 7th character 6 (bone involvement without necrosis)

Common Mistakes

HCC Buddy guidance

L97.303 — necrosis of muscle; muscle tissue death is present

L97.306 — bone involvement without necrosis; bone exposed but viable, no necrosis

L89.5- — Pressure ulcer codes; use only when ulcer is caused by sustained pressure, not vascular or other non-pressure etiology

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 L97.304 an HCC code?

Yes. L97.304 maps to Chronic Ulcer of Skin, Except Pressure under the CMS-HCC V28 risk adjustment model (and Chronic Ulcer of Skin, Except Pressure under V24).

HCC Category Mapping

V28HCC 380, Chronic Ulcer of Skin, Except Pressure

0.426

V24HCC 161, Chronic Ulcer of Skin, Except Pressure

0.426

ESRDHCC 161, Chronic Ulcer of Skin, Except Pressure

0.000

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.

MEAT Criteria for L97.304

For L97.304to 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 L97.304 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

L97.304 is the ICD-10-CM diagnosis code for non-pressure chronic ulcer of unspecified ankle with necrosis of bone. A long-lasting open sore on the ankle (not from pressure) where the bone tissue has died and deteriorated. L97.304 sits in the ICD-10-CM chapter for diseases of the skin and subcutaneous tissue (l00-l99), within the section covering other disorders of the skin and subcutaneous tissue (l80-l99).

Under the CMS-HCC V28 risk adjustment model, L97.304 maps to Chronic Ulcer of Skin, Except Pressure (HCC 380) with a community, non-dual, aged base RAF weight of 0.426. The V24 model used during the PY2024–PY2025 transition mapped L97.304 the same way and at the same RAF weight. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.

Bone necrosis is the most severe non-pressure ulcer category; requires imaging confirmation (X-ray or MRI) documented in the record. Because L97.304 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for L97.304 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Bone necrosis is the most severe non-pressure ulcer category; requires imaging confirmation (X-ray or MRI) documented in the record
•This indicates osteomyelitis risk; coordinate with infectious disease documentation if applicable

Clinical Significance

Non-pressure chronic ulcers of the lower extremity are significant indicators of underlying vascular disease, diabetes, or other systemic conditions that impair wound healing. Bone necrosis represents the most severe stage of chronic ulceration with osteomyelitis risk, frequently necessitating aggressive surgical intervention and reflecting profound underlying disease burden.

Documentation Requirements

✓Ulcer site documented as unspecified ankle with clear laterality (unspecified side)
✓Confirmation that the ulcer is chronic (present for extended duration, not acute)
✓Etiology documented as non-pressure (e.g., venous stasis, arterial insufficiency, diabetic, or other non-pressure cause)
✓Clinical assessment of wound depth and tissue involvement
✓Documentation of necrotic bone within or at the base of the wound
✓Imaging or clinical findings confirming bone necrosis (osteonecrosis)
✓Assessment for osteomyelitis with appropriate workup (imaging, labs, culture if indicated)
✓Surgical consultation documentation if applicable

Commonly Confused Codes

•L97.303: necrosis of muscle; muscle tissue death is present
•L97.306: bone involvement without necrosis; bone exposed but viable, no necrosis
•L89.5-: Pressure ulcer codes; use only when ulcer is caused by sustained pressure, not vascular or other non-pressure etiology