M86.149
BillableOther acute osteomyelitis, unspecified hand
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.149 an HCC code?
Yes. M86.149 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 M86.149
For M86.149 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 M86.149 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.149 is the ICD-10-CM diagnosis code for other acute osteomyelitis, unspecified hand. A sudden bone infection in the hand bones where it is not specified whether the right or left hand is affected. M86.149 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, M86.149 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, M86.149 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.
Attempt to clarify laterality from clinical documentation or imaging before using this unspecified code. Because M86.149 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 M86.149 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Attempt to clarify laterality from clinical documentation or imaging before using this unspecified code
- •Hand infections require prompt treatment, so laterality should be determined for proper clinical management
Clinical Significance
Acute osteomyelitis of unspecified hand represents incomplete documentation of a serious bone infection that threatens hand function. The lack of laterality specification limits accurate risk stratification and treatment planning, warranting provider queries for complete documentation.
Documentation Requirements
- ✓Documentation of hand bone infection without laterality
- ✓Evidence of acute onset bone infection
- ✓Clinical signs of osteomyelitis in hand bones
- ✓Imaging confirmation of hand bone involvement
- ✓Laboratory evidence of active infection
- ✓Provider query for laterality specification
- ✓Documentation of functional assessment
- ✓Treatment plan appropriate for hand osteomyelitis
Commonly Confused Codes
- •L03.119 — Cellulitis of unspecified finger (soft tissue infection)
- •M86149 vs M86141/142 — When laterality can be determined
- •M86649 — Chronic osteomyelitis with draining sinus of unspecified hand
- •M86249 — Subacute osteomyelitis of unspecified hand
- •S62.90XA — Unspecified fracture of unspecified wrist and hand