Crystal's Coder Hub🧬 ICD-10-CM G61.0 — Guillain-Barré Syndrome
Billable Code Confirmed
ICD-10-CM G61.0 is a valid, billable 5-character ICD-10-CM code for FY2026.¹ Characters 1-3 (G61) define the category “Inflammatory polyneuropathy”; the fourth character (0) specifies Guillain-Barré syndrome as the distinct condition. No additional characters are required — this is a terminal, fully specified billable code.
Non-Billable Parent Code — Never Submit This
- ❌
G61— 3-character header — does not specify the type of inflammatory polyneuropathyAlways submit G61.0 (all 5 characters) when Guillain-Barré syndrome is the documented diagnosis.
Clinical Context: Includes Miller Fisher Syndrome and Acute Infective Polyneuritis
ICD-10-CM G61.0 captures not only classic Guillain-Barré syndrome but also Miller Fisher Syndrome (MFS) and Acute (post-)infective polyneuritis as official inclusion terms.¹² MFS — characterized by the triad of ophthalmoplegia, ataxia, and areflexia — is coded to G61.0 and does not have its own separate ICD-10-CM code. Coders should recognize these alternate clinical presentations to avoid undercoding.
Code Classification
ICD-10-CM Diagnosis Code — wRVU, assistant-at-surgery payable status, and global period fields are not applicable to diagnosis codes. For associated inpatient procedures and outpatient services, refer to the CPT Procedural Crosswalk and ICD-10-PCS Crosswalk sections below. G61.0 functions as an MCC when sequenced as a secondary diagnosis, which significantly impacts DRG weight.³
🔍 Code Description
ICD-10-CM G61.0 classifies Guillain-Barré syndrome (GBS), an acute, immune-mediated polyneuropathy characterized by rapidly progressive ascending weakness, areflexia, and varying degrees of sensory and autonomic dysfunction.¹ It is the most common cause of acute flaccid paralysis worldwide, typically triggered by a preceding infection (most commonly Campylobacter jejuni, cytomegalovirus, Epstein-Barr virus, or Zika virus) that induces molecular mimicry leading to autoimmune attack on peripheral nerve components.⁴
The classic form, Acute Inflammatory Demyelinating Polyneuropathy (AIDP), targets the myelin sheath of peripheral nerves; axonal variants (AMAN, AMSAN) attack the axon directly and are associated with poorer functional outcomes.⁴ Autonomic involvement — including cardiac arrhythmias, blood pressure lability, and urinary retention — is present in up to 70% of cases and is a major driver of ICU admission and resource utilization.⁵ Respiratory muscle weakness requiring mechanical ventilation occurs in approximately 25-30% of hospitalized patients.⁵
🌳 Code Tree / Hierarchy
G61 — Inflammatory polyneuropathy ❌ Non-billable
│
├── G61.0 — Guillain-Barré syndrome ◀ THIS CODE ✅ Billable
├── G61.1 — Serum neuropathy ✅ Billable
├── G61.81 — Chronic inflammatory demyelinating polyneuropathy (CIDP) ✅ Billable
├── G61.82 — Multifocal motor neuropathy ✅ Billable
└── G61.89 — Other inflammatory polyneuropathies ✅ Billable
GBS vs. CIDP — Critical Distinction
G61.0 (GBS) and G61.81 (CIDP) are frequently confused. GBS is an acute monophasic illness with nadir typically at 2-4 weeks; CIDP is a chronic, relapsing-remitting or progressive demyelinating neuropathy lasting >8 weeks. The clinical timeline in the documentation is the key differentiator — a CDI query should be initiated if the provider uses ambiguous language like “demyelinating neuropathy” without specifying acute vs. chronic.
✅ Includes
The following clinical terms and scenarios map to G61.0 when documented:
- Guillain-Barré syndrome (all subtypes unless separately specified)
- Acute inflammatory demyelinating polyneuropathy (AIDP)
- Acute motor axonal neuropathy (AMAN)
- Acute motor-sensory axonal neuropathy (AMSAN)
- Miller Fisher Syndrome (MFS) — ophthalmoplegia, ataxia, areflexia triad
- Acute (post-)infective polyneuritis
- Landry’s ascending paralysis
- Barré-Guillain disease or syndrome
- Encephalomyeloradiculitis (acute)
❌ Excludes
Excludes 1 — Cannot Be Coded Simultaneously with G61.0
| Code | Description | Note |
|---|---|---|
| G51.0 | Bell’s palsy | Facial nerve palsy is a separate peripheral nerve condition; if GBS is the underlying cause of facial weakness, code G61.0 only — do not add G51.0 unless a truly separate, unrelated Bell’s palsy is independently documented |
Excludes 1 Violation Risk
A patient with GBS may develop facial diplegia as a manifestation of GBS itself — this is not a separately coded Bell’s palsy. Only code G51.0 if the provider documents a clearly separate, unrelated facial nerve palsy distinct from the GBS episode. Coding both simultaneously without independent documentation is an Excludes 1 violation.
📋 Clinical Overview
GBS Variant Comparison — Impact on Documentation and Coding
All GBS variants map to G61.0, but understanding their clinical differences helps coders recognize appropriate documentation and initiate targeted CDI queries for specificity in the medical record.
| Feature | AIDP | AMAN | Miller Fisher Syndrome |
|---|---|---|---|
| Pathology | Demyelinating | Motor axonal | Axonal; anti-GQ1b Ab |
| Weakness Pattern | Ascending limb weakness | Ascending motor; rapid | Ophthalmoplegia, ataxia, areflexia |
| Sensory Involvement | Yes | Minimal | Minimal |
| Respiratory Risk | High (~30%) | High | Low |
| CSF Findings | Albuminocytologic dissociation | Albuminocytologic dissociation | Normal or mild protein elevation |
| ICD-10-CM Code | G61.0 | G61.0 | G61.0 |
CDI Query Trigger — Document the GBS Variant
While all variants map to G61.0, accurate medical record documentation of the variant (AIDP, AMAN, MFS) is important for clinical quality metrics, research, and future ICD-10-CM revision alignment. If the provider documents only “GBS” without variant specification, a query can clarify for record completeness — though it will not change the ICD-10-CM code assignment.
Manifestations & Symptom Burden
GBS is a high-acuity diagnosis with numerous codeable manifestations that should be captured to fully represent clinical complexity and support DRG optimization:
- Respiratory failure (J96.00): Acute respiratory failure without hypoxia — approximately 25-30% of GBS patients require mechanical ventilation; this is a true MCC and dramatically shifts DRG weight⁵
- Autonomic dysfunction: Cardiac arrhythmias (I49.9), blood pressure lability, urinary retention (R33.9) — code each when documented
- Dysphagia (R13.10): Bulbar involvement affects swallowing; code separately when documented
- Pain (G89.29): Neuropathic pain is present in up to 66% of GBS patients — code when documented as a distinct management concern⁵
- hyponatremia (E87.1): SIADH-related hyponatremia is a recognized GBS complication; code when documented
Coding Manifestations
Always code the documented manifestations to fully capture the patient’s complexity. Examples include:
- [[J96.00]] — Acute respiratory failure, unspecified whether with hypoxia or hypercapnia
- R13.10 — Dysphagia, unspecified
- R33.9 — Retention of urine, unspecified
💰 HCC Risk Adjustment (CMS-HCC v28)
| Field | Detail |
|---|---|
| CMS-HCC Model Version | v28 (2024-2025 Implementation) |
| HCC Assignment | ❌ Not HCC-Mapped |
| HCC Category | N/A |
| RAF Coefficient | N/A |
G61.0 does not map to an HCC category under CMS-HCC Model v28 and does not independently contribute to a patient’s RAF score.⁶
Risk Adjustment — Capture Sequelae and Chronic Complications
Because GBS itself carries no HCC weight, ensure that any chronic residual conditions following GBS are captured when documented — e.g., post-GBS peripheral neuropathy, chronic respiratory failure, or muscle weakness. Additionally, any HCC-mapped triggering conditions (e.g., HIV infection, malignancy) that precipitated GBS should be captured annually. IVIG administration in Medicare Advantage patients may trigger quality metric review even absent HCC impact.
🏥 MS-DRG Assignment
MDC 01 — Diseases and Disorders of the Nervous System
| DRG | Title | Est. Relative Weight* |
|---|---|---|
| DRG 091 | Other Disorders of Nervous System with MCC | ~1.50-1.70 |
| DRG 092 | Other Disorders of Nervous System with CC | ~0.90-1.10 |
| DRG 093 | Other Disorders of Nervous System without CC/MCC | ~0.65-0.80 |
Approximate. Verify against IPPS FY2026 Final Rule tables.⁷
Sequencing and MCC Impact
G61.0 itself is classified as an MCC when sequenced as a secondary diagnosis.³ When GBS is the principal diagnosis, the DRG tier (091 vs. 092 vs. 093) is determined by secondary diagnoses. Acute respiratory failure (J96.00) as a secondary code is also an MCC and will lock in DRG 091 — the highest-weight tier. Failure to capture and code respiratory failure, autonomic instability, or aspiration pneumonia in a GBS patient represents significant DRG underweighting and compliance risk. Always query CDI when these complications are clinically present but not explicitly documented.
🔗 Related ICD-10-CM Codes
Inflammatory Polyneuropathy Family — G61 Block
| Code | Description |
|---|---|
| G61.0 | Guillain-Barré syndrome ← This Code |
| G61.1 | Serum neuropathy |
| G61.81 | Chronic inflammatory demyelinating polyneuropathy (CIDP) |
| G61.82 | Multifocal motor neuropathy |
| G61.89 | Other inflammatory polyneuropathies |
Related Peripheral Neuropathy and Differential Codes
| Code | Description |
|---|---|
| G62.9 | Polyneuropathy, unspecified (use when GBS is not confirmed) |
| G62.81 | Critical illness polyneuropathy |
| G70.01 | Myasthenia gravis with (acute) exacerbation (key GBS differential — flaccid weakness without areflexia pattern) |
| G12.21 | Amyotrophic lateral sclerosis (ALS — ascending weakness differential) |
🛠️ Commonly Associated CPT Codes (Neurology / Critical Care Setting)
Inpatient and Profee Setting Context
GBS is predominantly an inpatient diagnosis with high ICU utilization. In the profee setting, neurology E/M services, electrodiagnostic studies, and procedure codes for IVIG infusion or plasmapheresis are the most common associated CPT codes. Modifier -25 is required on the E/M when electrodiagnostic testing is performed on the same date.
| CPT Code | Description | Profee Coding Notes |
|---|---|---|
| 95910 | Nerve conduction studies; 7-8 studies | Critical for GBS diagnosis confirmation; Modifier -25 on same-day E/M; Modifier -26 if profee interpretation only |
| 95886 | Needle EMG, each extremity, complete study | Frequently paired with NCS to characterize AIDP vs. axonal variant; Modifier -25 on E/M |
| 96365 | IV infusion, therapeutic; initial, up to 1 hour | IVIG administration — bill with applicable IVIG HCPCS drug code (e.g., J1459); not bundled with drug code |
| 36514 | Therapeutic apheresis; plasma exchange | Plasmapheresis — alternative first-line GBS treatment; billed per session |
| 99223 | Initial hospital care, high complexity | Typically appropriate given MDM complexity of GBS admission |
| 99291 | Critical care, first 30-74 minutes | Use when patient requires ICU-level critical care management for GBS with respiratory failure |
NCCI Bundling Considerations
- Nerve Conduction Studies (95910) billed on the same date as an E/M (99223 or 99232) require Modifier -25 on the E/M to confirm a separately identifiable service above and beyond pre-service work of the diagnostic study.
- IVIG drug code (e.g., J1459) and infusion administration (96365) are separately billable — they are not bundled with each other.
🔬 ICD-10-PCS Crosswalk (Inpatient Procedures)
When G61.0 is an inpatient diagnosis, these PCS codes are frequently relevant for associated inpatient procedures.
| PCS Section | Body System | Root Operation | Clinical Application |
|---|---|---|---|
| 5 (Extracorporeal or Systemic Assistance and Performance) | Physiological Systems | Performance | Mechanical ventilation >96 hours for GBS respiratory failure — 5A1955Z |
| 3 (Administration) | Circulatory | Introduction | IVIG administration via peripheral IV — 3E033GC |
| 6 (Extracorporeal or Systemic Therapies) | Physiological Systems | Pheresis | Therapeutic plasma exchange (plasmapheresis) — 6A550ZZ |
| 0 (Medical and Surgical) | Respiratory System | Bypass | Tracheostomy for prolonged ventilator dependence in GBS — 0B110F4 |
💊 Coding Scenarios and Examples
Scenario 1 — Inpatient: Classic GBS with Respiratory Failure
Clinical Vignette: A 38-year-old female presents with a 5-day history of ascending bilateral lower extremity weakness and tingling following a Campylobacter gastroenteritis 3 weeks prior. On admission, she has areflexia of all four extremities, vital capacity of 1.2L (42% predicted), and is admitted to the neurology ICU. Lumbar puncture reveals albuminocytologic dissociation (elevated protein, normal WBC). NCS confirms AIDP pattern. She is intubated on day 2 for respiratory failure and receives IVIG 2g/kg over 5 days.
Principal Diagnosis:
- G61.0 — Guillain-Barré syndrome (reason for admission; confirmed by NCS and LP findings)
Secondary Diagnoses:
- J96.00 — Acute respiratory failure, unspecified (MCC — respiratory muscle weakness requiring intubation; drives DRG 091)
- B94.8 — Sequelae of other specified infectious and parasitic diseases (post-Campylobacter trigger when documented)
- R29.2 — Abnormal reflex (documented areflexia — codeable as separate finding)
MS-DRG Assignment: DRG 091 — Other Disorders of Nervous System with MCC. J96.00 (acute respiratory failure) as secondary MCC combined with G61.0 as principal locks in highest-weight DRG tier.
Scenario 2 — Inpatient: Miller Fisher Syndrome Variant
Clinical Vignette: A 55-year-old male presents with 4 days of double vision, unsteady gait, and difficulty swallowing. Exam reveals bilateral ophthalmoplegia, truncal ataxia, and areflexia. Anti-GQ1b antibody is positive. Neurology documents “Miller Fisher Syndrome, a variant of Guillain-Barré syndrome.” MRI brain is unremarkable. Patient is admitted for monitoring and IVIG administration.
Principal Diagnosis:
- G61.0 — Guillain-Barré syndrome *(Miller Fisher Syndrome is an official inclusion term under G61.0)*¹
Secondary Diagnoses:
- H51.9 — Unspecified disorder of binocular movement (documented bilateral ophthalmoplegia)
- R13.10 — Dysphagia, unspecified (documented swallowing difficulty — code separately when managed)
- R27.0 — Ataxia, unspecified (documented truncal ataxia)
MS-DRG Assignment: DRG 092 or 093 depending on whether secondary diagnoses qualify as CC. R13.10 (dysphagia) may qualify as CC — verify with FY2026 CC/MCC tables.
Scenario 3 — CDI Query: GBS vs. CIDP Documentation Ambiguity
Clinical Vignette: A 62-year-old female is admitted for progressive bilateral lower extremity weakness and sensory loss over 10 weeks. The neurology note documents “chronic demyelinating polyneuropathy, possibly GBS vs. CIDP — further workup pending.” NCS shows diffuse demyelination. The coder cannot confirm G61.0 (GBS) vs. G61.81 (CIDP) based on available documentation.
Action / Outcome: The 10-week symptom timeline exceeds the typical GBS nadir of 2-4 weeks and raises strong clinical suspicion for CIDP. However, the provider has not confirmed a diagnosis. A CDI query is required before coding.
Query Response: Provider documents: “Based on symptom duration exceeding 8 weeks and NCS pattern, this is Chronic Inflammatory Demyelinating Polyneuropathy (CIDP), not GBS.”
Corrected ICD-10-CM Coding:
- G61.81 — Chronic inflammatory demyelinating polyneuropathy (confirmed definitive diagnosis after CDI clarification)
⚠️ Coding Pitfalls and Tips
| Pitfall or Tip | |
|---|---|
| ❌ | Coding Facial Diplegia as Bell’s Palsy in GBS. Facial weakness in GBS is a manifestation of the syndrome — adding G51.0 violates Excludes 1. Only code G51.0 if a truly independent, unrelated Bell’s palsy is documented.¹ |
| ❌ | Using G61.0 for CIDP. When symptom duration exceeds 8 weeks or the provider documents “chronic” demyelinating polyneuropathy, query for CIDP (G61.81) — do not default to G61.0 without confirmed acute/monophasic documentation. |
| ❌ | Failing to Code Respiratory Failure as Secondary. Acute respiratory failure (J96.00) in a GBS patient is an MCC that elevates DRG to 091. Missing this code when intubation is documented is a significant compliance and revenue integrity issue.⁷ |
| ✅ | Recognize All G61.0 Inclusion Terms. Miller Fisher Syndrome and Acute (post-)infective polyneuritis are official inclusion terms — do not leave these coded to less specific codes like G62.9 when GBS/MFS is documented.¹ |
| ✅ | Capture All Autonomic Manifestations Separately. Cardiac arrhythmia, urinary retention, and blood pressure lability are codeable comorbidities in GBS that may qualify as CC and improve DRG grouping — always code when documented. |
| ✅ | Query the Trigger When Documented. If a provider documents a preceding infection (Campylobacter, CMV, EBV, Zika), code the post-infectious sequela code (B94.8) when appropriate per Official Guidelines — this adds clinical context and supports the admission narrative. |
📚 Sources
- CMS/NCHS. ICD-10-CM Official Guidelines for Coding and Reporting, FY2026. Chapter 6 — Diseases of the Nervous System (G00-G99); G61.0 inclusion terms and Excludes 1 notes.
- AAPC. ICD-10-CM Code G61.0 — Guillain-Barré Syndrome. Code descriptor, inclusion terms, and official long descriptor. https://www.aapc.com/codes/icd-10-codes/G61.0
- CMS. IPPS Final Rule FY2026 — MS-DRG Definitions Manual v43. G61.0 MCC designation; MDC 01 DRG 091-093 grouper logic.
- Willison HJ, Jacobs BC, van Doorn PA. Guillain-Barré syndrome. Lancet. 2016;388(10045):717-727. doi:10.1016/S0140-6736(16)00339-1 (Pathophysiology, variant classification, triggering infections.)
- van den Berg B, Walgaard C, Drenthen J, et al. Guillain-Barré syndrome: pathogenesis, diagnosis, treatment and prognosis. Nat Rev Neurol. 2014;10(8):469-482. (Respiratory failure incidence, autonomic involvement, pain prevalence.)
- CMS. 2025-2026 Medicare Advantage Risk Adjustment — CMS-HCC Model v28 ICD-10-CM Mappings. G61.0 — no HCC assignment.
- CMS. IPPS Final Rule FY2026 — MS-DRG Definitions Manual v43. Complications and comorbidity (CC/MCC) table; J96.00 MCC designation.