2027 ICD-10-CM Diagnosis Code G37.89Other specified demyelinating diseases of central nervous system
ICD-10-CM Codes›G00–G99›G35-G37›G37
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 198
- Chronic Condition
G37.89 is a billable ICD-10-CM diagnosis code for other specified demyelinating diseases of central nervous system. 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 160 closely related codes. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other nervous system disorders (neither hereditary nor degenerative).
For Medicare Advantage risk adjustment, G37.89 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
Code Classification
Medicare Risk Adjustment (HCC)Billing
G37.89 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.
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.
- 4H leukodystrophy
- Central nervous system demyelination due to Lyme borreliosis
- Central pontine myelinolysis
- Clinically isolated syndrome
- Clinically isolated syndrome of brainstem
- Clinically isolated syndrome of cerebellum
- Demyelination due to systemic vasculitis
- Demyelination of central nervous system due to Behcet disease
- Dysmyelination of cerebral white matter
- Extrapontine myelinolysis
- Hypomyelination of central nervous system structure
- Hypomyelination of cerebral white matter
- Hypomyelination of early myelinating structures
- Inherited disorder of folate metabolism
- Late tooth eruption
- Leukoencephalopathy, ataxia, hypodontia, hypomyelination syndrome
- Mitchell syndrome
- Mixed sensory-motor polyneuropathy
- Monofocal clinically isolated syndrome
- Motor polyneuropathy
- MTHFS-related developmental delay, microcephaly, short stature, epilepsy syndrome
- Mucocutaneous Behçet disease
- Multifocal clinically isolated syndrome
- Osmotic demyelination syndrome
- Patchy demyelination of subcortical white matter
- Radiologically isolated syndrome
- Sensory polyneuropathy
- Severe demyelination of white matter
- Vasculitis due to systemic disease
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to G37.89: its own notes plus those printed at Chapter 6. A note printed at a category, block or chapter applies to every code under it.
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.
- 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.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Disease, diseased See Also: Syndrome;
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Degenerative Nerve Diseases
Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical condition such as alcoholism, a tumor, or a stroke. Other causes may include toxins, chemicals, and viruses.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Code History & ChangesHistory
Replacement G37.89 replaces the following previously assigned code(s):
- G37.8 - Oth demyelinating diseases of central nervous system
Questions About G37.89Overview
What is the ICD-10 code for other specified demyelinating diseases of central nervous system?
The ICD-10-CM code for other specified demyelinating diseases of central nervous system is G37.89 (sometimes written as G3789). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is G37.89 a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other specified demyelinating diseases of central nervous system on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does G37.89 group to?
When other specified demyelinating diseases of central nervous system 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 G37.89 a CC or MCC?
CMS lists G37.89 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 160 closely related codes in its exclusion list.
What HCC is G37.89?
G37.89 (other specified demyelinating diseases of central nervous system) 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. It does not map to any RxHCC in the Part D prescription drug model.
Does G37.89 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, G37.89 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.
