What is ICD-10 code G61.0?

G61.0 is the ICD-10-CM diagnosis code for Guillain-Barre syndrome. An acute autoimmune condition where the body's immune system attacks nerve cells, causing rapid muscle weakness and potentially paralysis that typically develops over days to weeks. G61.0 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G61.0 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. G61.0 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. G61.0 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 G61.0?

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. G61.0 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 G61.0?

This is an acute condition; ensure documentation supports the diagnosis with clinical presentation and diagnostic findings Consider sequencing this as a principal diagnosis if it is the primary reason for admission Because G61.0 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.

G61.0 ICD-10 Code: Guillain-Barre syndrome

ICD-10-CM Code View

HCC Buddy Code Card

Digital ICD-10 code-book layout with official code detail, always-visible risk models, Code Trumping, and Buddy coding guidance.

Code lookupG61.0Effective 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)

G61.0

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

Guillain-Barre syndrome

An acute autoimmune condition where the body's immune system attacks nerve cells, causing rapid muscle weakness and potentially paralysis that typically develops over days to weeks.

Buddy Insight

Guillain-Barre syndrome is a rapidly progressive autoimmune polyneuropathy that can lead to respiratory failure and death if untreated.

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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Compare selected patient codes to show trumped or trumps impact.

Code Book Path

Official

G61Inflammatory polyneuropathy

G61.0Guillain-Barre syndrome

Inclusion Terms

Official

Acute (post-)infective polyneuritis
Miller Fisher Syndrome

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G61.0 in this effective period.

Related Child Codes

Official

G61.1Serum neuropathy

G61.8Other inflammatory polyneuropathies

G61.9Inflammatory polyneuropathy, unspecified

Includes

Official

ICD-10-CM does not list Includes notes for G61.0 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G61.0 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G61.0 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G61.0 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G61.0 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Clinical presentation: acute ascending weakness, areflexia, sensory changes

Diagnostic confirmation: nerve conduction studies/electromyography findings, cerebrospinal fluid analysis showing albuminocytologic dissociation

Temporal course: onset over days to weeks with progressive pattern

Treatment plan: intravenous immunoglobulin or plasmapheresis

MEAT Support

HCC Buddy guidance

Clinical presentation: acute ascending weakness, areflexia, sensory changes

Diagnostic confirmation: nerve conduction studies/electromyography findings, cerebrospinal fluid analysis showing albuminocytologic dissociation

Temporal course: onset over days to weeks with progressive pattern

Treatment plan: intravenous immunoglobulin or plasmapheresis

Audit Caution

HCC Buddy guidance

Coding G61.0 for a patient who is in the sequelae phase rather than the acute phase — use G65.0 for residual effects

Failing to distinguish from CIDP (G61.81) when the neuropathy has been present for more than 8 weeks

Not querying the provider when documentation is vague about whether the condition is acute Guillain-Barre syndrome versus another inflammatory polyneuropathy

Missing the opportunity to capture this high-value HCC code when the diagnosis is documented but buried in the history

Common Mistakes

HCC Buddy guidance

G61.81 — Chronic inflammatory demyelinating polyneuritis (CIDP) is the chronic form lasting >8 weeks; Guillain-Barre syndrome is acute

G61.89 — Other inflammatory polyneuropathies is a catch-all for inflammatory neuropathies that do not meet Guillain-Barre syndrome criteria

G65.0 — Sequelae of Guillain-Barre syndrome is for residual effects after the acute phase has resolved, not the active disease

G62.81 — Critical illness polyneuropathy develops in ICU patients from sepsis/critical illness, not autoimmune etiology

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 G61.0 an HCC code?

Yes. G61.0 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.

MEAT Criteria for G61.0

For G61.0to 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 G61.0 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

G61.0 is the ICD-10-CM diagnosis code for guillain-barre syndrome. An acute autoimmune condition where the body's immune system attacks nerve cells, causing rapid muscle weakness and potentially paralysis that typically develops over days to weeks. G61.0 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, G61.0 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.

This is an acute condition; ensure documentation supports the diagnosis with clinical presentation and diagnostic findings. Because G61.0 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 G61.0 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is an acute condition; ensure documentation supports the diagnosis with clinical presentation and diagnostic findings
•Consider sequencing this as a principal diagnosis if it is the primary reason for admission

Clinical Significance

Guillain-Barre syndrome is a rapidly progressive autoimmune polyneuropathy that can lead to respiratory failure and death if untreated. It is critical for risk adjustment because it reflects high-acuity neurological disease requiring intensive monitoring, immunotherapy, and often prolonged rehabilitation. Accurate capture ensures appropriate resource allocation for these complex patients.

Documentation Requirements

✓Clinical presentation: acute ascending weakness, areflexia, sensory changes
✓Diagnostic confirmation: nerve conduction studies/electromyography findings, cerebrospinal fluid analysis showing albuminocytologic dissociation
✓Temporal course: onset over days to weeks with progressive pattern
✓Treatment plan: intravenous immunoglobulin or plasmapheresis
✓Functional status: respiratory function monitoring, degree of paralysis
✓Provider's explicit diagnosis of Guillain-Barre syndrome

Commonly Confused Codes

•G61.81 — Chronic inflammatory demyelinating polyneuritis (CIDP) is the chronic form lasting >8 weeks; Guillain-Barre syndrome is acute
•G61.89 — Other inflammatory polyneuropathies is a catch-all for inflammatory neuropathies that do not meet Guillain-Barre syndrome criteria
•G65.0 — Sequelae of Guillain-Barre syndrome is for residual effects after the acute phase has resolved, not the active disease
•G62.81 — Critical illness polyneuropathy develops in ICU patients from sepsis/critical illness, not autoimmune etiology