G61.9
BillableInflammatory polyneuropathy, unspecified
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G61.9 an HCC code?
Yes. G61.9 maps to Myasthenia Gravis/Myoneural Disorders and Guillain-Barre Syndrome/Inflammatory and Toxic Neuropathy under the V24 model but is not retained in V28.
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 G61.9
For G61.9to 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 G61.9 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G61.9 is the ICD-10-CM diagnosis code for inflammatory polyneuropathy, unspecified. Inflammation affecting multiple nerves throughout the body where the specific cause or type cannot be determined. G61.9 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 older CMS-HCC V24 model, G61.9 maps to Myasthenia Gravis/Myoneural Disorders and Guillain-Barre Syndrome/Inflammatory and Toxic Neuropathy (HCC 75) with a community, non-dual, aged base RAF weight of 0.472. 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.
This is an unspecified code; query the provider for more specific diagnostic information before coding. Because G61.9 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 G61.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •This is an unspecified code; query the provider for more specific diagnostic information before coding
- •Review all available test results and clinical findings to determine if a more specific G61 code applies
Clinical Significance
Inflammatory polyneuropathy, unspecified represents an inflammatory nerve condition where the specific type cannot be determined. While this captures disease complexity for risk adjustment, it is a non-specific code that ideally should be replaced with a more precise diagnosis. It still reflects a patient with significant neurological disease burden requiring treatment.
Documentation Requirements
- ✓Evidence of polyneuropathy: clinical symptoms of weakness, sensory changes, or pain in multiple nerve distributions
- ✓Laboratory or electrodiagnostic evidence of inflammatory etiology
- ✓Documentation explaining why a more specific type cannot be determined
- ✓Treatment plan addressing the inflammatory polyneuropathy
- ✓Follow-up plan for additional diagnostic workup to refine the diagnosis
- ✓Provider's clear diagnosis of inflammatory polyneuropathy
Commonly Confused Codes
- •G61.0 — Guillain-Barre syndrome should be used when acute ascending paralysis is documented with diagnostic confirmation
- •G61.81 — CIDP should be used for chronic demyelinating polyneuropathy lasting beyond 8 weeks
- •G61.89 — Other inflammatory polyneuropathies is preferred when the provider specifies a type but it does not have its own code
- •G62.9 — Polyneuropathy, unspecified is even more general and does not specify inflammatory etiology