M86.539
BillableOther chronic hematogenous osteomyelitis, unspecified radius and ulna
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.539 an HCC code?
Yes. M86.539 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 M86.539
For M86.539 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 M86.539 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.539 is the ICD-10-CM diagnosis code for other chronic hematogenous osteomyelitis, unspecified radius and ulna. A chronic bone infection of the radius and ulna (forearm bones) that developed from bacteria spreading through the bloodstream, affecting an unspecified side. M86.539 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, M86.539 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, M86.539 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 documentation specifies 'chronic hematogenous' osteomyelitis to distinguish from other types like contiguous or post-traumatic. Because M86.539 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 M86.539 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
This chronic hematogenous osteomyelitis of unspecified radius/ulna represents a persistent bone infection that developed from bacteria spreading through the bloodstream. The unspecified laterality indicates incomplete documentation but still captures the chronic nature and anatomical involvement, requiring ongoing medical management and monitoring.
Documentation Requirements
- ✓Documentation of chronic duration (>6 weeks or recurrent pattern)
- ✓Evidence of hematogenous spread (bloodstream origin)
- ✓Involvement of radius and/or ulna bones
- ✓Radiographic evidence of bone infection or destruction
- ✓Laboratory markers of infection (ESR, CRP, WBC)
- ✓Clinical presentation consistent with chronic osteomyelitis
- ✓Treatment response or failure documentation
- ✓Absence of draining sinus or acute presentation