M86.262
BillableSubacute osteomyelitis, left tibia and fibula
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.262 an HCC code?
Yes. M86.262 maps to Bone/Joint/Muscle Infections/Necrosis under the CMS-HCC V28 risk adjustment model (and Bone/Joint/Muscle Infections/Necrosis 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 M86.262
For M86.262 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 M86.262 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.262 is the ICD-10-CM diagnosis code for subacute osteomyelitis, left tibia and fibula. A bone infection in the left shin bone and smaller bone of the lower leg that develops gradually over weeks to months. M86.262 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering other osteopathies (m86-m90).
Under the CMS-HCC V28 risk adjustment model, M86.262 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.209. Under the older V24 model, M86.262 mapped to the same category but with a base RAF weight of 0.482 — 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.
Verify left-sided location is explicitly documented. Because M86.262 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 M86.262 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify left-sided location is explicitly documented
- •Document any associated swelling, drainage, or functional impairment
Clinical Significance
Subacute osteomyelitis of the left tibia and fibula is an intermediate-stage bone infection developing over weeks to months that significantly impacts patient mobility and quality of life. The involvement of both lower leg bones creates complex treatment challenges and increases risk of complications including chronic infection, growth abnormalities, and permanent functional impairment.
Documentation Requirements
- ✓Documentation of subacute osteomyelitis affecting left tibia and fibula
- ✓Clinical evidence of infection developing over weeks to months
- ✓Specific left-sided involvement documented
- ✓Radiological confirmation of bone infection in tibia and/or fibula
- ✓Laboratory markers consistent with ongoing infection
- ✓Blood and/or bone culture results when available
- ✓Functional assessment including ambulation difficulties
- ✓Treatment response documentation and follow-up plans