M86.319
BillableChronic multifocal osteomyelitis, unspecified shoulder
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.319 an HCC code?
Yes. M86.319 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 M86.319
For M86.319 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 M86.319 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.319 is the ICD-10-CM diagnosis code for chronic multifocal osteomyelitis, unspecified shoulder. A long-standing bone infection affecting multiple bones with shoulder involvement, but the specific shoulder (right or left) is not specified. M86.319 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, M86.319 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, M86.319 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.
Use this code only when laterality cannot be determined; attempt to obtain clarification from the provider for more specific coding. Because M86.319 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 M86.319 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Use this code only when laterality cannot be determined; attempt to obtain clarification from the provider for more specific coding.
- •Document that the shoulder is involved but laterality is unspecified.
Clinical Significance
Chronic multifocal osteomyelitis with unspecified shoulder laterality indicates a serious systemic bone infection requiring aggressive treatment protocols. While anatomically less specific than lateralized codes, it still represents significant morbidity and healthcare resource demands characteristic of chronic multifocal bone infections.
Documentation Requirements
- ✓Documentation of chronic osteomyelitis diagnosis
- ✓Evidence of multifocal bone involvement pattern
- ✓Shoulder involvement clearly stated but laterality unspecified
- ✓Laboratory confirmation of infectious process
- ✓Radiographic evidence supporting diagnosis
- ✓Current and historical treatment documentation
- ✓Patient response to therapy assessments
- ✓Complication monitoring and management notes
Commonly Confused Codes
- •M86.311 — Chronic multifocal osteomyelitis, right shoulder (has laterality specified)
- •M86.312 — Chronic multifocal osteomyelitis, left shoulder (has laterality specified)
- •M86.619 — Other chronic osteomyelitis, unspecified shoulder (not multifocal)
- •M86.419 — Chronic osteomyelitis with draining sinus, unspecified shoulder (different type)