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G36.0

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🧬 ICD-10-CM G36.0 — Neuromyelitis Optica [Devic’s Disease]

Billable Code Confirmed

ICD-10-CM G36.0 is a valid, billable 4-character diagnosis code. The first three characters (G36) define the category of acute disseminated demyelination, and the 4th character (0) specifies Neuromyelitis optica.

Clinical Context

Neuromyelitis optica (NMO), also known as Devic’s disease, is a severe autoimmune inflammatory demyelinating disease of the central nervous system. It primarily targets the optic nerves (causing optic neuritis) and the spinal cord (causing transverse myelitis). Unlike Multiple Sclerosis, NMO usually presents with more severe, isolated, and frequent attacks rather than a slow, insidious progression.

Code Classification

ICD-10-CM Diagnosis Code — wRVU, assistant payable, and global period fields are not applicable. See CPT Procedural Crosswalk and ICD-10-PCS Crosswalk sections for associated procedural billing.

🔍 Code Description

ICD-10-CM G36.0 identifies Neuromyelitis optica. This condition is distinct from Multiple Sclerosis (MS) because of its specific pathophysiology—often linked to aquaporin-4 (AQP4) antibodies—which leads to astrocytopathy and subsequent demyelination. The clinical course involves relapses, and early aggressive treatment is required to prevent permanent neurological deficits, such as blindness or paralysis.

🌳 Code Tree / Hierarchy

G36 Other acute disseminated demyelination ❌ Non-billable
│
├── G36.0 Neuromyelitis optica [Devic's disease] ◀ THIS CODE ✅ Billable
├── G36.1 Acute and subacute hemorrhagic leukoencephalitis [Hurst's disease] ✅ Billable
├── G36.8 Other specified acute disseminated demyelination ✅ Billable
└── G36.9 Acute disseminated demyelination, unspecified ✅ Billable

✅ Includes

The following terms map to G36.0:

  • Devic’s disease
  • Neuromyelitis optica (NMO)
  • NMO Spectrum Disorder (NMOSD) — Note: If a provider documents NMOSD, ensure clinical correlation with AQP4 status if available, but G36.0 remains the appropriate coding choice.

❌ Excludes

Excludes 1 — Cannot Be Coded Simultaneously

CodeDescriptionNote
G35.-Multiple SclerosisNMO and MS are distinct clinical entities. G36.0 should not be used if the provider has definitively diagnosed MS.

📋 Clinical Overview

Required Coding Considerations

  • Manifestations: NMO often results in specific neurological deficits. Always code associated manifestations such as:
    • H53.19 (Other subjective visual disturbances) or H46.9 (Unspecified optic neuritis).
    • G82.50 (Quadriplegia, unspecified) or other myelitis-related weakness codes.
  • Antibody Status: While the ICD-10-CM does not have a unique code for “AQP4-positive,” this is the defining laboratory marker. Coding this status is not required for the G36.0 code itself but supports medical necessity for high-cost biologics.

💰 HCC Risk Adjustment (CMS-HCC v28)

FieldDetail
CMS-HCC Modelv28
HCC Assignment✅ HCC 76
RAF ImpactCaptures the long-term complexity of a demyelinating condition.

Annual Capture

Because this is a chronic, life-long autoimmune condition, you must Monitor, Evaluate, Assess, and Treat (MEAT) this condition during an active encounter at least annually to substantiate the HCC capture.

🏥 DRG Assignment (Inpatient)

MDC 01 — Diseases and Disorders of the Nervous System

DRGTitle
DRG 058Multiple Sclerosis and Cerebellar [[AtaxiaM. E. A. T Criteria]] with MCC
DRG 059Multiple Sclerosis and Cerebellar Ataxia with CC
DRG 060Multiple Sclerosis and Cerebellar Ataxia without CC/MCC

Note: NMO groups to the same DRGs as MS.

🛠️ Commonly Associated CPT Codes (Profee)

CPT CodeDescriptionwRVUAssistant PayableGlobal
99214Established patient office visit (Moderate MDM)1.92NoXXX
70553MRI Brain w/ & w/o contrast~2.50NoXXX
62270Diagnostic lumbar puncture2.14No000

💊 Coding Scenarios

Scenario 1 — Inpatient Exacerbation of NMO

Clinical Vignette: A 42-year-old female with known history of NMO is admitted with sudden loss of vision in the left eye and bilateral lower extremity weakness. MRI confirms acute optic neuritis and transverse myelitis. Attending physician documents “NMO relapse.”

Principal Diagnosis:

  • G36.0 — Neuromyelitis optica [Devic’s disease]

Secondary Diagnoses:

  • H46.01 — Optic neuritis, right eye (or appropriate laterality)
  • G04.1 — Tropical spastic paraplegia (or G37.3, Acute transverse myelitis, if specifically noted and not considered part of the NMO syndrome complex)

⚠️ Coding Pitfalls and Tips

Pitfall or Tip
❌Mislabeling as Multiple Sclerosis. G36.0 is an Excludes1 for MS (G35.A). If the documentation is unclear, query the provider.
❌Sequencing Symptom Codes. Do not sequence R-codes (like R27.0 Ataxia) ahead of G36.0 if the definitive NMO diagnosis is documented.
✅Capture the Relapse. If the patient is admitted for a “relapse” or “exacerbation” of NMO, ensure the code G36.0 is sequenced as the principal diagnosis.
✅Query for Myelitis Specifics. If the patient has transverse myelitis as part of the NMO, ensure the documentation clarifies it is due to the NMO (G36.0) to ensure the clinical picture is captured accurately.
✅Annual MEAT Documentation. Even if the patient is stable, the record must reflect continued management (e.g., current biologics, routine labs, neuro monitoring) to maintain HCC validity for the current year.

📚 Sources

1. CMS/NCHS. *ICD-10-CM Official Guidelines for Coding and Reporting, FY2026.*
2. Wingerchuk, D. M., et al. (2015). International consensus diagnostic criteria for neuromyelitis optica spectrum disorder. *Neurology*, 85(2), 177-189. (Source for diagnostic and pathophysiology distinction).
3. CMS. *2025-2026 Medicare Advantage Risk Adjustment — CMS-HCC Model v28 ICD-10-CM Mappings.*
4. American Medical Association (AMA). *CPT Professional Edition 2026.*
G35.A

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