M86.30
BillableChronic multifocal osteomyelitis, unspecified site
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.30 an HCC code?
Yes. M86.30 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 M86.30
For M86.30 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 M86.30 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.30 is the ICD-10-CM diagnosis code for chronic multifocal osteomyelitis, unspecified site. A long-standing bone infection affecting multiple bones throughout the body, with the specific location unspecified. M86.30 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, M86.30 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, M86.30 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.
Request clarification from the provider regarding which bones are affected, as more specific codes exist for common sites. Because M86.30 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 M86.30 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Request clarification from the provider regarding which bones are affected, as more specific codes exist for common sites.
- •Chronic multifocal osteomyelitis often requires investigation for underlying systemic conditions; ensure appropriate workup is documented.
Clinical Significance
Chronic multifocal osteomyelitis at unspecified site represents a long-standing bone infection affecting multiple locations throughout the body, indicating severe systemic disease with significant morbidity. This condition requires prolonged antibiotic therapy, potential surgical intervention, and comprehensive management to prevent complications such as pathologic fractures, sepsis, and permanent disability.
Documentation Requirements
- ✓Clear documentation of chronic multifocal osteomyelitis
- ✓Evidence of long-standing infection (typically months to years)
- ✓Documentation of involvement at multiple bone sites
- ✓Clinical evidence of chronic bone infection with systemic manifestations
- ✓Imaging findings consistent with chronic multifocal osteomyelitis
- ✓Laboratory markers supporting chronic infectious process
- ✓Culture results and antibiotic resistance patterns
- ✓Assessment of functional limitations and quality of life impact