M87.046
BillableIdiopathic aseptic necrosis of unspecified finger(s)
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.046 an HCC code?
Yes. M87.046 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 M87.046
For M87.046 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 M87.046 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.046 is the ICD-10-CM diagnosis code for idiopathic aseptic necrosis of unspecified finger(s). Death of bone tissue in finger(s) without infection, occurring without a known cause, when the specific finger or side is not specified. This condition affects the fingers and can result in pain and functional impairment. M87.046 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, M87.046 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, M87.046 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. Because M87.046 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 M87.046 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 the provider if laterality information is available elsewhere in the medical record
Clinical Significance
Idiopathic aseptic necrosis of unspecified finger(s) represents bone death in digital bones when laterality is not documented, affecting finger function and potential collapse of affected bone. This condition affects the fingers and can result in pain and functional impairment requiring hand surgery evaluation and management.
Documentation Requirements
- ✓Documentation of aseptic necrosis affecting finger bones
- ✓Confirmation of idiopathic etiology without identifiable cause
- ✓Imaging studies demonstrating bone necrosis in finger phalanges
- ✓Absence of laterality specification in medical documentation
- ✓Exclusion of infectious causes through clinical assessment
- ✓Finger functional assessment including range of motion and grip contribution
- ✓Treatment plan documentation including therapeutic interventions
- ✓Pain management strategies and functional impact on hand activities