M86.532
BillableOther chronic hematogenous osteomyelitis, left radius and ulna
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.532 an HCC code?
Yes. M86.532 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 M86.532
For M86.532 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 M86.532 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.532 is the ICD-10-CM diagnosis code for other chronic hematogenous osteomyelitis, left radius and ulna. A chronic bone infection of the left forearm bones (radius and ulna) that developed from a bloodstream infection. M86.532 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, M86.532 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, M86.532 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.
Confirm documentation specifies left forearm to support this laterality-specific code. Because M86.532 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 M86.532 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Confirm documentation specifies left forearm to support this laterality-specific code
- •The radius and ulna are the two bones of the forearm; this code applies when either or both are infected
Clinical Significance
Chronic hematogenous osteomyelitis represents a serious bone infection that originated from bloodstream bacteria and has persisted over time, indicating failure of initial treatment or host immune response. This condition significantly impacts patient mobility, quality of life, and requires long-term antibiotic therapy with potential surgical intervention.
Documentation Requirements
- ✓Confirmation of chronic nature (duration >6 weeks or recurrent episodes)
- ✓Evidence of hematogenous origin (bloodstream spread vs direct inoculation)
- ✓Specific anatomical location: left radius and ulna
- ✓Imaging findings (X-ray, MRI, or bone scan) showing bone infection
- ✓Laboratory evidence (elevated ESR, CRP, or positive blood cultures)
- ✓Clinical symptoms (bone pain, fever, functional limitation)
- ✓Treatment history and response to prior therapy
- ✓Exclusion of acute osteomyelitis or other bone pathology