What is ICD-10 code G65.1?

G65.1 is the ICD-10-CM diagnosis code for Sequelae of other inflammatory polyneuropathy. Long-term complications or residual effects remaining after recovery from inflammatory nerve damage conditions other than Guillain-Barré syndrome. It belongs to the ICD-10-CM chapter for diseases of the nervous system (g00-g99). G65.1 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G65.1 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. G65.1 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. G65.1 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for G65.1?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. G65.1 was a payment HCC under V24 (Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome) but the V28 recalibration removed it from the risk adjustment model. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting G65.1?

Specify which inflammatory polyneuropathy the sequelae are from in the clinical documentation Ensure the acute phase has resolved and current symptoms represent lasting effects Because G65.1 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

G65.1: Sequelae of other inflammatory polyneuropathy — ICD-10 | Myasthenia Gravis/Myoneural

ICD-10-CM Code View

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Code lookupG65.1Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Polyneuropathies and other disorders of the peripheral nervous system (G60-G65)

G65.1

Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidance

Sequelae of other inflammatory polyneuropathy

Long-term complications or residual effects remaining after recovery from inflammatory nerve damage conditions other than Guillain-Barré syndrome.

Buddy Insight

Sequelae of other inflammatory polyneuropathy represents the lasting effects of previously resolved inflammatory neuropathies other than Guillain-Barre syndrome.

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Mapped

HCC 75

Myasthenia Gravis/Myoneural C...

RAF 0.425

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 75

Myasthenia Gravis/Myoneural C...

RAF 0.0

RXHCC

Mapped

HCC 158

Guillain-Barre Syndrome and O...

RAF 0.0

Code Trumping

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Code Book Path

Official

G65Sequelae of inflammatory and toxic polyneuropathies

G65.1Sequelae of other inflammatory polyneuropathy

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for G65.1 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G65.1 in this effective period.

Related Child Codes

Official

G65.0Sequelae of Guillain-Barre syndrome

G65.2Sequelae of toxic polyneuropathy

Includes

Official

ICD-10-CM does not list Includes notes for G65.1 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G65.1 in this effective period.

Code First

Official

condition resulting from (sequela) of inflammatory and toxic polyneuropathies

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G65.1 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G65.1 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

History of prior inflammatory polyneuropathy (specifying which type when known)

Documentation that the acute inflammatory phase has resolved

Current residual symptoms and functional limitations

Ongoing treatment or rehabilitation for residual deficits

MEAT Support

HCC Buddy guidance

History of prior inflammatory polyneuropathy (specifying which type when known)

Documentation that the acute inflammatory phase has resolved

Current residual symptoms and functional limitations

Ongoing treatment or rehabilitation for residual deficits

Audit Caution

HCC Buddy guidance

Using the active inflammatory polyneuropathy code when the acute phase has resolved and only sequelae remain

Not specifying the original inflammatory condition in the documentation, making it difficult to validate the sequelae code

Confusing with G65.0 when the original condition was Guillain-Barre syndrome — use the more specific sequelae code

Failing to also code specific residual deficits such as neuropathic pain or muscle weakness

Common Mistakes

HCC Buddy guidance

G65.0 — Sequelae of Guillain-Barre syndrome is specifically for Guillain-Barre syndrome residual effects; use G65.1 for all other inflammatory polyneuropathy sequelae

G61.89 — Other inflammatory polyneuropathies is for the active disease, not the sequelae phase

G65.2 — Sequelae of toxic polyneuropathy is for residual effects of toxic exposure, not inflammatory conditions

G62.9 — Polyneuropathy, unspecified does not capture the sequelae nature of the condition

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is G65.1 an HCC code?

Yes. G65.1 maps to Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome under the V24 model but is not retained in V28.

HCC Category Mapping

V24HCC 75, Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome

0.425

ESRDHCC 75, Myasthenia Gravis/Myoneural Conditions and Guillain-Barre Syndrome

0.000

RxHCCHCC 158, Guillain-Barre Syndrome and Other Polyneuropathies

0.000

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.

Work G65.1 in the Code Book — tabular path, V28 RAF, and MEAT checklist →

MEAT Criteria for G65.1

For G65.1to 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 G65.1 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

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What This Code Means

G65.1 is the ICD-10-CM diagnosis code for sequelae of other inflammatory polyneuropathy. Long-term complications or residual effects remaining after recovery from inflammatory nerve damage conditions other than Guillain-Barré syndrome. G65.1 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, G65.1 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.

Specify which inflammatory polyneuropathy the sequelae are from in the clinical documentation. Because G65.1 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 G65.1 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Specify which inflammatory polyneuropathy the sequelae are from in the clinical documentation
•Ensure the acute phase has resolved and current symptoms represent lasting effects

Clinical Significance

Sequelae of other inflammatory polyneuropathy represents the lasting effects of previously resolved inflammatory neuropathies other than Guillain-Barre syndrome. These residual effects may include chronic weakness, pain, or sensory deficits requiring ongoing management. Proper coding captures the continuing functional impact on patients who have recovered from the acute phase.

Documentation Requirements

✓History of prior inflammatory polyneuropathy (specifying which type when known)
✓Documentation that the acute inflammatory phase has resolved
✓Current residual symptoms and functional limitations
✓Ongoing treatment or rehabilitation for residual deficits
✓Provider's explicit statement that current symptoms are sequelae of the prior inflammatory condition
✓Time interval since the acute episode

Commonly Confused Codes

•G65.0: Sequelae of Guillain-Barre syndrome is specifically for Guillain-Barre syndrome residual effects; use G65.1 for all other inflammatory polyneuropathy sequelae
•G61.89: Other inflammatory polyneuropathies is for the active disease, not the sequelae phase
•G65.2: Sequelae of toxic polyneuropathy is for residual effects of toxic exposure, not inflammatory conditions
•G62.9: Polyneuropathy, unspecified does not capture the sequelae nature of the condition