2027 ICD-10-CM Diagnosis Code G36.0Neuromyelitis optica [Devic]

ICD-10-CM Codes›G00–G99›G35-G37›G36

ICD-10-CM G36.0
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G36.0 is a billable ICD-10-CM diagnosis code for neuromyelitis optica [Devic]. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 58 through 60. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 9 closely related codes. Coders also document this condition as demyelination of spinal cord. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (neither hereditary nor degenerative).

For Medicare Advantage risk adjustment, G36.0 maps to CMS-HCC Category 198 (Multiple Sclerosis) under the V28 model, adding a risk factor of about 0.647 for a community, non-dual, aged beneficiary in payment year 2027.

Code Identity

ICD-10-CM Code
G36.0
Billable Status
Yes — Valid for Submission
Code Describes
Neuromyelitis optica [Devic]
Short Description
Neuromyelitis optica [Devic]
Same as the full description in the CMS dataset.
Parent Code
G36
Other acute disseminated demyelination

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG35-G37Demyelinating diseases of the central nervous system
CategoryG36Other acute disseminated demyelination
This CodeG36.0Neuromyelitis optica [Devic]

Medicare Risk Adjustment (HCC)Billing

G36.0 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.

CMS-HCC V28 Category (Payment Model)
HCC 198— Multiple Sclerosis
Payment HCC · PY 2027 one of 20 ICD-10-CM codes in this category
Risk Adjustment Factor (RAF) Weight
+0.647
community, non-dual, aged · ranges 0.226–1.143 across segments
Hierarchy
Top of its hierarchy
HCC 198 is not superseded by any other condition category
Prior Model (CMS-HCC V24)
HCC 77
V24 retired V28 pays 100% of MA risk scores since PY 2026
Other CMS Models
PACE (CMS-HCC V22): HCC 77 · ESRD (V21): HCC 77 · ESRD (V24): HCC 77
ESRD V21 weights: 0.069 dialysis, 0.000–0.546 functioning graft · ESRD V24 weights: 0.111 dialysis, 0.042–1.113 functioning graft
Part D (RxHCC)
RxHCC 159 — Multiple Sclerosis
also risk-adjusts in the Part D prescription drug model (V08)

Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Demyelination of spinal cord
  • Neuromyelitis optica

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G36.0: its own notes plus those printed at G36 and Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Applicable To

Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.

  • Demyelination in optic neuritis

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From G36 Other acute disseminated demyelination applies to 4 codes
  • postinfectious encephalitis and encephalomyelitis NOS (G04.01)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

On G36.0 itself
  • optic neuritis NOS (H46)
From Chapter 6 (G00-G99) Diseases of the nervous system applies to 700 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G36.0, its category, or a range that includes it.

Excludes1 1

These codes carry an Excludes1 note naming G36.0: they are not reported together with it, unless the two conditions are unrelated.

  • G37.3 Acute transverse myelitis in demyelinating disease of central nervous system
    neuromyelitis optica [Devic] (G36.0)

Excludes2 1

These codes carry an Excludes2 note naming G36.0: its condition is not part of those codes, and both may be reported when the patient has both.

  • H46 Optic neuritis
    neuromyelitis optica [Devic] (G36.0)

Code Also 1

These codes say G36.0 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • G37.81 Myelin oligodendrocyte glycoprotein antibody disease
    neuromyelitis optica (G36.0)

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR NVS020
Other nervous system disorders (neither hereditary nor degenerative)
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Neuromyelitis Optica

    a syndrome characterized by acute optic neuritis; myelitis, transverse; demyelinating and/or necrotizing lesions in the optic nerves and spinal cord; and presence of specific autoantibodies to aquaporin 4.

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Convert G36.0 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
341.0 Neuromyelitis optica
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G36.0Overview

What is the ICD-10 code for neuromyelitis optica [Devic]?

The ICD-10-CM code for neuromyelitis optica [Devic] is G36.0 (sometimes written as G360). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is G36.0 (Other acute disseminated demyelination) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report neuromyelitis optica [Devic] on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What MS-DRG does G36.0 group to?

When neuromyelitis optica [Devic] is the principal diagnosis on an inpatient stay, it groups to MS-DRG 60, 58, 59, with relative weights from 0.9248 to 1.8430 depending on complications. Higher weights mean higher Medicare reimbursement.

Is G36.0 a CC or MCC?

CMS lists G36.0 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 9 closely related codes in its exclusion list.

Can G36.0 be reported with G04.01?

Not as a rule. The Excludes1 note at G36, which applies to G36.0, lists "postinfectious encephalitis and encephalomyelitis NOS (G04.01)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).

What HCC is G36.0?

G36.0 (neuromyelitis optica [Devic]) maps to CMS-HCC Category 198 (Multiple Sclerosis), commonly written as HCC 198, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 77 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 159.

Does G36.0 risk-adjust for Medicare Advantage payment?

Yes. When documented and reported on a Medicare Advantage encounter, G36.0 adds a risk adjustment factor of about 0.647 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.226 to 1.143 depending on the payment segment). HCC 198 sits at the top of its hierarchy, so no other condition category supersedes it. See the full factor table on the HCC 198 category page.