T32.66
BillableCorrosions involving 60-69% of body surface with 60-69% third degree corrosion
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is T32.66 an HCC code?
Yes. T32.66 maps to Severe Skin Burn or Condition under the CMS-HCC V28 risk adjustment model (and Severe Skin Burn or Condition 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 T32.66
For T32.66 to 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 T32.66 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
T32.66 is the ICD-10-CM diagnosis code for corrosions involving 60-69% of body surface with 60-69% third degree corrosion. Chemical burn affecting 60-69% of the body surface with 60-69% deep tissue damage (third degree corrosion). This is a critical chemical injury where the majority of affected area involves full-thickness burns. T32.66 sits in the ICD-10-CM chapter for injury, poisoning and certain other consequences of external causes (s00-t88), within the section covering burns and corrosions of multiple and unspecified body regions (t30-t32).
Under the CMS-HCC V28 risk adjustment model, T32.66 maps to Severe Skin Burn or Condition (HCC 385) with a community, non-dual, aged base RAF weight of 0.350. Under the older V24 model, T32.66 mapped to the same category but with a base RAF weight of 0.517 — 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.
This code indicates the most severe category within the 60-69% body surface range and requires immediate specialized burn care. Because T32.66 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 T32.66 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This code indicates the most severe category within the 60-69% body surface range and requires immediate specialized burn care
- •Always include the seventh character extension for proper documentation of care episode
Clinical Significance
This represents critical chemical burns involving 60-69% of the body where the majority of affected area has full-thickness destruction (60-69% third-degree), indicating catastrophic injury with extremely high mortality risk. These patients require immediate burn center care with aggressive surgical intervention and face significant risk of death or severe permanent disability.
Documentation Requirements
- ✓Total body surface area documentation (60-69%)
- ✓Third-degree burn percentage (60-69%)
- ✓Specific chemical agent and concentration
- ✓Time of exposure and contact duration
- ✓Current care phase and treatment response
- ✓Detailed anatomical involvement
- ✓Associated complications and organ failure
- ✓Multiple surgical interventions and grafting