M86.219
BillableSubacute osteomyelitis, unspecified shoulder
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.219 an HCC code?
Yes. M86.219 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 M86.219
For M86.219 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 M86.219 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.219 is the ICD-10-CM diagnosis code for subacute osteomyelitis, unspecified shoulder. A bone infection in the shoulder of unspecified side that develops gradually over weeks to months, causing inflammation and potential bone damage. M86.219 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, M86.219 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, M86.219 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 from documentation; query provider if possible for clarification. Because M86.219 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 M86.219 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 from documentation; query provider if possible for clarification
- •This is a less specific code; attempt to obtain laterality information before final coding
Clinical Significance
Subacute osteomyelitis of unspecified shoulder represents a bone infection with intermediate timeline affecting shoulder anatomy without laterality specification. This diagnosis warrants provider queries for laterality and careful monitoring to prevent chronic progression while preserving shoulder function.
Documentation Requirements
- ✓Documentation of shoulder bone infection without laterality
- ✓Evidence of subacute infection timeline
- ✓Clinical presentation of shoulder osteomyelitis
- ✓Imaging confirmation of shoulder bone involvement
- ✓Laboratory support for ongoing infection
- ✓Provider query for laterality specification
- ✓Assessment of shoulder function and mobility
- ✓Treatment plan appropriate for shoulder anatomy
Commonly Confused Codes
- •M86119 — Acute hematogenous osteomyelitis of unspecified shoulder
- •M86619 — Chronic osteomyelitis with draining sinus of unspecified shoulder
- •M86319 — Chronic multifocal osteomyelitis of unspecified shoulder
- •M86211/212 — Right/left specific codes when laterality available
- •M25519 — Pain in unspecified shoulder