I96
BillableGangrene, not elsewhere classified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is I96 an HCC code?
Yes. I96 maps to Atherosclerosis of the Extremities with Ulceration or Gangrene under the CMS-HCC V28 risk adjustment model (and Atherosclerosis of the Extremities with Ulceration or Gangrene under V24).
HCC Category Mapping
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 I96
For I96to 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 I96 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
I96 is the ICD-10-CM diagnosis code for gangrene, not elsewhere classified. Death and decay of body tissue due to loss of blood supply or severe infection, not classified under other specific conditions. I96 sits in the ICD-10-CM chapter for diseases of the circulatory system (i00-i99), within the section covering other and unspecified disorders of the circulatory system (i95-i99).
Under the CMS-HCC V28 risk adjustment model, I96 maps to Atherosclerosis of the Extremities with Ulceration or Gangrene (HCC 263) with a community, non-dual, aged base RAF weight of 0.742. Under the older V24 model, I96 mapped to the same category but with a base RAF weight of 0.860 — V28 recalibrated weights across the entire model. 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.
Specify the anatomical site of gangrene with an additional code when possible. Because I96 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 I96 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Specify the anatomical site of gangrene with an additional code when possible
- •Investigate whether the gangrene is due to diabetes, atherosclerosis, or other underlying conditions
Clinical Significance
Gangrene not elsewhere classified represents tissue death due to inadequate blood supply or severe infection, a critical condition that often requires urgent surgical intervention including possible amputation. This diagnosis indicates severe end-organ damage and carries high mortality and morbidity risk. It is a major driver of healthcare resource utilization due to surgical costs, prolonged hospitalization, wound care, rehabilitation, and prosthetic needs.
Documentation Requirements
- ✓Explicit documentation of gangrene (dry, wet, or gas gangrene type when specified)
- ✓Anatomical site of gangrenous tissue identified
- ✓Underlying etiology documented (peripheral vascular disease, diabetes, infection, trauma)
- ✓Extent of tissue involvement described
- ✓Vascular assessment findings (pulses, perfusion status, imaging results)
- ✓Treatment plan including surgical intervention, debridement, or amputation if applicable
- ✓Assessment of viability of surrounding tissue
Excludes 1 — Do NOT code together
- gangrene in atherosclerosis of native arteries of the extremities (I70.26)
- gangrene in hernia (K40.1, K40.4, K41.1, K41.4, K42.1, K43.1-, K44.1, K45.1, K46.1)
- gangrene in other peripheral vascular diseases (I73.-)
- gangrene of certain specified sites - see Alphabetical Index
- gas gangrene (A48.0)
- pyoderma gangrenosum (L88)
Commonly Confused Codes
- •E11.52 — Type 2 diabetes mellitus with diabetic peripheral angiopathy with gangrene; use when gangrene is directly attributable to diabetes
- •I70.261/I70.262 — Atherosclerosis of native arteries of extremities with gangrene; use when gangrene is due to peripheral artery disease
- •A48.0 — Gas gangrene; use specifically for clostridial gas gangrene infection
- •R02 — This code was deleted and replaced by I96; do not use R02
- •L03.xxx — Cellulitis codes; cellulitis is infection without tissue death and should not be confused with gangrene
- •T79.A — Traumatic compartment syndrome; may lead to gangrene but is coded separately