L89.304
BillablePressure ulcer of unspecified buttock, stage 4
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is L89.304 an HCC code?
Yes. L89.304 maps to Pressure Ulcer of Skin with Full Thickness Skin Loss under the CMS-HCC V28 risk adjustment model (and Pressure Ulcer of Skin with Necrosis Through to Muscle, Tendon, or Bone 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 L89.304
For L89.304 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 L89.304 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
L89.304 is the ICD-10-CM diagnosis code for pressure ulcer of unspecified buttock, stage 4. A severe pressure ulcer (bedsore) on the buttocks that has penetrated through multiple layers of skin and tissue, classified as the most advanced stage. L89.304 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, L89.304 maps to Pressure Ulcer of Skin with Full Thickness Skin Loss (HCC 379) with a community, non-dual, aged base RAF weight of 0.662. Under the older CMS-HCC V24 model, L89.304 maps to Pressure Ulcer of Skin with Necrosis Through to Muscle, Tendon, or Bone (HCC 157) with a community, non-dual, aged base RAF weight of 1.071. 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.
Stage 4 indicates full-thickness skin loss with exposed bone, tendon, or muscle; document the extent of tissue damage clearly. Because L89.304 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 L89.304 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Stage 4 indicates full-thickness skin loss with exposed bone, tendon, or muscle; document the extent of tissue damage clearly
- •Verify the anatomical site is truly unspecified buttock rather than right or left to avoid miscoding
Clinical Significance
Stage 4 pressure ulcers of the unspecified buttock represent the most severe wound classification with exposed bone, tendon, or muscle. The ischial tuberosity is the most common bony prominence involved in buttock stage 4 wounds in seated patients. These carry high risk for ischial osteomyelitis, perirectal abscess, and systemic infection, often requiring surgical debridement and reconstruction.
Documentation Requirements
- ✓Anatomical location specified as buttock (query for laterality)
- ✓Stage explicitly documented as stage 4
- ✓Specific exposed structures identified
- ✓Complete wound measurements
- ✓Undermining and tunneling documentation
- ✓Imaging for osteomyelitis if bone is exposed
- ✓Wound cultures
- ✓Nutritional labs
- ✓Surgical consultation
- ✓Comprehensive treatment plan