M86.632
BillableOther chronic osteomyelitis, left radius and ulna
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M86.632 an HCC code?
Yes. M86.632 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 M86.632
For M86.632 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 M86.632 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M86.632 is the ICD-10-CM diagnosis code for other chronic osteomyelitis, left radius and ulna. A chronic bone infection in the left forearm bones (radius and ulna) characterized by persistent inflammation and bone involvement. M86.632 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, M86.632 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, M86.632 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 'left' laterality is clearly documented in the clinical notes. Because M86.632 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 M86.632 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify 'left' laterality is clearly documented in the clinical notes
- •Note any drainage, sinus tracts, or sequestrum formation as these may affect treatment planning
Clinical Significance
Chronic osteomyelitis of the left radius and ulna represents a serious bone infection affecting both forearm bones, severely compromising upper extremity function and hand use. This condition significantly impacts activities of daily living and may require extensive rehabilitation services and adaptive equipment.
Documentation Requirements
- ✓Confirmation of chronic duration (minimum 6 weeks or recurrent episodes)
- ✓Specific documentation of left radius and/or ulna involvement
- ✓Non-hematogenous etiology (contiguous spread or direct inoculation)
- ✓Radiographic evidence of bone infection or destruction
- ✓Laboratory studies supporting chronic infection process
- ✓Functional assessment of left forearm and hand
- ✓Documentation of antibiotic therapy and surgical procedures
- ✓Assessment of occupational and daily living limitations
Commonly Confused Codes
- •M86.532 — Other chronic hematogenous osteomyelitis, left radius and ulna (hematogenous origin)
- •M86.631 — Other chronic osteomyelitis, right radius and ulna (different laterality)
- •M86.432 — Chronic osteomyelitis with draining sinus, left radius and ulna (has sinus tract)
- •M86.132 — Other acute osteomyelitis, left radius and ulna (acute presentation)
- •M89.032 — Algoneurodystrophy, left forearm (nerve-related condition)