Skip to content
HCC Buddy home

G37.89 ICD-10-CM Code: Other specified demyelinating diseases of central nervous system

G37.89 maps to CMS-HCC V28 198. A source-labeled RAF reference is available. Documentation must support MEAT. MEAT criteria · RAF Calculator · HCC Buddy coding tools

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.

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Demyelinating diseases of the central nervous system (G35-G37)

G37.89

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

Other specified demyelinating diseases of central nervous system

Other specified conditions involving damage to nerve insulation in the brain and spinal cord that do not fit into standard demyelinating disease categories.

Buddy the Bee presenting code insight

Buddy Insight

Other specified demyelinating diseases of the central nervous system captures demyelinating conditions that have been identified by the provider but do not fit other specific G37 categories.

CMS-HCC V28

HCC 198

Code-level coefficient reference

CMS-HCC V24

Historical

Historical

Not used for CY2026 payment

ACA/HHS

N/A

—

Not mapped

ESRD/PACE

HCC 77

Code-level coefficient reference

RXHCC

N/A

—

Not mapped

Code Book Path

Official
G37Other demyelinating diseases of central nervous system
G37.8Other specified demyelinating diseases of central nervous system
G37.89Other specified demyelinating diseases of central nervous system

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for G37.89 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G37.89 in this effective period.

Related Child Codes

Official
G37.81Myelin oligodendrocyte glycoprotein antibody disease

Includes

Official

ICD-10-CM does not list Includes notes for G37.89 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G37.89 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G37.89 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G37.89 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G37.89 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance
Documentation specifying the exact demyelinating disease
Neuroimaging showing demyelinating lesions
Evidence that more specific codes (G37.0-G37.81) have been considered and excluded
Neurological examination findings consistent with demyelinating disease

MEAT Support

HCC Buddy guidance
Documentation specifying the exact demyelinating disease
Neuroimaging showing demyelinating lesions
Evidence that more specific codes (G37.0-G37.81) have been considered and excluded
Neurological examination findings consistent with demyelinating disease

Audit Caution

HCC Buddy guidance
Using G37.89 when a more specific demyelinating disease code exists
Confusing 'other specified' (G37.89) with 'unspecified' (G37.9) — the former requires a named condition
Not documenting the specific demyelinating condition, making the code unsupportable on audit
Defaulting to G37.89 without thoroughly reviewing available specific codes in the G35-G37 range

Common Mistakes

HCC Buddy guidance
G37.9 — Demyelinating disease of CNS, unspecified; use when the specific type is not determined
G37.81 — MOGAD; has its own specific code and should not use G37.89
G35 — Multiple sclerosis; the most common demyelinating disease with its own code
G37.5 — Concentric sclerosis (Balo); has its own specific code

Current with CMS: FY2026 ICD-10-CM Apr 1 update (effective Apr 1 – Sep 30, 2026) · CMS-HCC V28, 100% phased in for payment year 2026. FY2027 code set already staged for October 1, 2026. How HCC Buddy stays current →

Is G37.89 an HCC code?

Yes. G37.89 (Other specified demyelinating diseases of central nervous system) maps to HCC 198, Multiple Sclerosis under the CMS-HCC V28 risk adjustment model, with a source-labeled community non-dual aged reference coefficient of 0.647. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes. It is billable for payment year 2026.

Coder answer: G37.89 is billable and maps to V28 HCC 198, Multiple Sclerosis. Open it in the Code Book for the tabular path, RAF, and MEAT checklist.

Code
G37.89
Description
Other specified demyelinating diseases of central nervous system
HCC (V28)
HCC 198 — Multiple Sclerosis
RAF reference coefficient
0.647
Billable
Yes
Payment year
2026

HCC Category Mapping

V28HCC 198, Multiple Sclerosis
0.647
ESRDHCC 77, Multiple Sclerosis
Not separately weighted

These are source-labeled model coefficients, not member totals. A category may still be removed by hierarchy or model cleanup rules. Weights are not directly comparable across models: CMS-HCC V28 and V24 use Community, Non-Dual, Aged; ESRD uses the dialysis continuing-enrollee model; RxHCC is the Part D continuing-enrollee, non-low-income, aged weight (a larger scale than CMS-HCC). ACA/HHS has no single weight — it varies by metal level. Actual per-patient RAF contribution depends on member context, hierarchy and cleanup rules, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains available for historical review.

Work G37.89 in the Code Book — tabular path, V28 RAF reference, and MEAT checklist →

MEAT Criteria for G37.89

For G37.89 to 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 G37.89 during that encounter, not just copy-forwarded from a problem list.

Coder workflow notes

Get the V28 mapping + MEAT cheat sheet

One printable reference: check representative V28 mappings and the documentation reminders your note needs. Free, no card.

Free PDF. No card. Unsubscribe anytime.

What This Code Means

G37.89 is the ICD-10-CM diagnosis code for other specified demyelinating diseases of central nervous system. Other specified conditions involving damage to nerve insulation in the brain and spinal cord that do not fit into standard demyelinating disease categories. G37.89 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering demyelinating diseases of the central nervous system (g35-g37).

Under the CMS-HCC V28 risk adjustment model, G37.89 maps to Multiple Sclerosis (HCC 198) with a source-labeled community, non-dual, aged reference coefficient of 0.647. No V24 mapping is shown for G37.89; use the applicable model and payment year when reviewing the V28 mapping. 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. Source-labeled code-level coefficients are references, not member totals. Actual contribution depends on complete member context, hierarchy and cleanup rules, interactions, and model year. HCC Buddy's RAF Calculator supports CMS-HCC V28 PY2026 and shows no score unless every required source and calculation check passes.

Use this code only when a specific demyelinating disease is documented but does not fit other G37 categories. Because G37.89 maps to an HCC category, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment. 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, source-labeled coefficient references, and MEAT documentation criteria for G37.89 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

  • •Use this code only when a specific demyelinating disease is documented but does not fit other G37 categories
  • •Always document the specific type of demyelinating disease in the medical record to support this code selection

Clinical Significance

Other specified demyelinating diseases of the central nervous system captures demyelinating conditions that have been identified by the provider but do not fit other specific G37 categories. These are typically rare conditions requiring specialized neurological management. Accurate coding ensures these uncommon but serious conditions are properly represented for risk adjustment.

Documentation Requirements

  • ✓Documentation specifying the exact demyelinating disease
  • ✓Neuroimaging showing demyelinating lesions
  • ✓Evidence that more specific codes (G37.0-G37.81) have been considered and excluded
  • ✓Neurological examination findings consistent with demyelinating disease
  • ✓Treatment plan for the specific condition
  • ✓Distinction from non-demyelinating neurological conditions

Commonly Confused Codes

  • •G37.9: Demyelinating disease of CNS, unspecified; use when the specific type is not determined
  • •G37.81: MOGAD; has its own specific code and should not use G37.89
  • •G35: Multiple sclerosis; the most common demyelinating disease with its own code
  • •G37.5: Concentric sclerosis (Balo); has its own specific code
  • •G36.8: Other specified acute disseminated demyelination; for acute presentations specifically

Child Codes

G37.81Myelin oligodendrocyte glycoprotein antibody disease
HCC 198
G37.89Other specified demyelinating diseases of central nervous system
HCC 198

Code Hierarchy

└G37Other demyelinating diseases of central nervous system└G37.8Other specified demyelinating diseases of central nervous system└G37.89Other specified demyelinating diseases of central nervous system
└G37.89Other specified demyelinating diseases of central nervous system

G37.89 code history

Code setChange
FY2024 (effective Oct 1, 2023)Added to the code set

Source: official CMS ICD-10-CM order and addenda files, FY2016 through FY2027.

Because G37.89 maps to an HCC category, the documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) before the diagnosis is used for risk adjustment.

G37.89 maps to CMS-HCC V28 category 198, Multiple Sclerosis. See the ICD-10 to HCC mapping hub for how the V28 crosswalk works. The mapping identifies a payment HCC category for G37.89. Review its source-labeled HCC coefficient above, check the RAF Calculator with complete member context for CMS-HCC V28 PY2026, and confirm the documentation the chart needs before the code is submitted. HCC Buddy shows no RAF score unless every required source and calculation check passes.

Work G37.89 in HCC Buddy

Open G37.89 in the Code Book for the full Index-to-Tabular path, MEAT checklist, and V28 HCC mapping, or in the Encoder to code from a keyword search. Pro includes 7 days to try everything, no card required.

Open in Code BookOpen in EncoderStart Pro