G61.82
BillableMultifocal motor neuropathy
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G61.82 an HCC code?
Yes. G61.82 maps to Chronic Inflammatory Demyelinating Polyneuritis under the CMS-HCC V28 risk adjustment model (and Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome 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 G61.82
For G61.82 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 G61.82 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G61.82 is the ICD-10-CM diagnosis code for multifocal motor neuropathy. A rare autoimmune nerve disorder that affects motor nerves in multiple, separate locations, causing progressive muscle weakness and atrophy. G61.82 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering polyneuropathies and other disorders of the peripheral nervous system (g60-g65).
Under the CMS-HCC V28 risk adjustment model, G61.82 maps to Chronic Inflammatory Demyelinating Polyneuritis (HCC 193) with a community, non-dual, aged base RAF weight of 0.000. Under the older CMS-HCC V24 model, G61.82 maps to Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome (HCC 75) with a community, non-dual, aged base RAF weight of 0.425. 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.
Ensure documentation specifies multifocal involvement rather than generalized polyneuropathy. Because G61.82 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 G61.82 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Ensure documentation specifies multifocal involvement rather than generalized polyneuropathy
- •This condition is distinct from other inflammatory polyneuropathies; verify diagnostic confirmation in records
Clinical Significance
Multifocal motor neuropathy is a rare immune-mediated neuropathy that selectively affects motor nerves in an asymmetric distribution, leading to progressive weakness without sensory loss. It requires expensive ongoing immunoglobulin therapy. Accurate coding is essential as it reflects a complex neurological condition with high treatment costs and significant disability potential.
Documentation Requirements
- ✓Asymmetric motor weakness documented in specific nerve distributions
- ✓Nerve conduction studies showing multifocal conduction block in motor nerves
- ✓Absence of significant sensory involvement (key distinguishing feature)
- ✓Anti-GM1 antibody testing results when available
- ✓Treatment with intravenous immunoglobulin or subcutaneous immunoglobulin
- ✓Provider's explicit diagnosis of multifocal motor neuropathy