What is ICD-10 code G50.9?

G50.9 is the ICD-10-CM diagnosis code for Disorder of trigeminal nerve, unspecified. A disorder of the trigeminal nerve where the specific type or nature of the condition is not specified or documented. It belongs to the ICD-10-CM chapter for diseases of the nervous system (g00-g99). G50.9 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G50.9 is part of the FY2026 ICD-10-CM code set published by the CMS National Center for Health Statistics and used on Medicare, Medicaid, and commercial claims in the United States.

Yes. G50.9 is a billable ICD-10-CM code that can be reported on professional and institutional claims as a primary or secondary diagnosis when the provider documentation supports the specific condition described. Billable codes in ICD-10-CM are coded to the highest level of specificity available for the documented diagnosis. G50.9 is current for fiscal year 2026 and remains in the active CMS ICD-10-CM code set published by the National Center for Health Statistics.

What is the V28 vs V24 difference for G50.9?

G50.9 does not map to a payment HCC under either the CMS-HCC V28 risk adjustment model or the older V24 model. V28 reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition. Because neither model rewards G50.9 with a risk adjustment factor, it contributes zero to a Medicare Advantage beneficiary's RAF score in either version. Coders should check whether provider documentation supports a more specific child code that does map to a payment HCC.

What should coders know when reporting G50.9?

This is a last-resort code; query the provider for more specific diagnosis when possible Avoid using this code if G50.0, G50.1, or G50.8 can be determined from documentation

G50.9 ICD-10 Code: Disorder of trigeminal nerve

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.

Code lookupG50.9Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Nerve, nerve root and plexus disorders (G50-G59)

G50.9

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

Disorder of trigeminal nerve, unspecified

A disorder of the trigeminal nerve where the specific type or nature of the condition is not specified or documented.

Buddy Insight

Disorder of the trigeminal nerve, unspecified, is used when a trigeminal nerve condition is diagnosed but the specific type is not documented or determinable from the record.

CMS-HCC V28

Not risk-adjusted for this model/period.

RAF 0

CMS-HCC V24

Not risk-adjusted for this model/period.

RAF 0

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Not risk-adjusted for this model/period.

RAF 0

RXHCC

Mapped

HCC 168

Trigeminal and Postherpetic N...

RAF 0.0

Code Trumping

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Code Book Path

Official

G50Disorders of trigeminal nerve

G50.9Disorder of trigeminal nerve, unspecified

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for G50.9 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G50.9 in this effective period.

Related Child Codes

Official

G50.0Trigeminal neuralgia

G50.1Atypical facial pain

G50.8Other disorders of trigeminal nerve

Includes

Official

disorders of 5th cranial nerve

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G50.9 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G50.9 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G50.9 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G50.9 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Provider documentation of a trigeminal nerve disorder (even without further specification)

Any available details about symptoms, distribution, or character of pain/dysfunction

Query opportunity: ask provider to specify type (neuralgia, neuropathy, atypical pain, other)

Neurological examination findings in trigeminal distribution

MEAT Support

HCC Buddy guidance

Provider documentation of a trigeminal nerve disorder (even without further specification)

Any available details about symptoms, distribution, or character of pain/dysfunction

Query opportunity: ask provider to specify type (neuralgia, neuropathy, atypical pain, other)

Neurological examination findings in trigeminal distribution

Audit Caution

HCC Buddy guidance

Accepting unspecified coding when the record contains enough information to assign a more specific code

Not querying the provider for trigeminal disorder type when clinical context suggests one

Confusing trigeminal nerve (CN V, sensation) disorders with facial nerve (CN VII, motor) disorders

Using this code for facial pain that has not been attributed to the trigeminal nerve

Common Mistakes

HCC Buddy guidance

G50.0 (Trigeminal neuralgia) — use when paroxysmal shock-like pain in trigeminal distribution is documented

G50.1 (Atypical facial pain) — use for continuous, poorly localized facial pain

G50.8 (Other disorders of trigeminal nerve) — use when a specific disorder is identified that is not neuralgia or atypical pain

R51.9 (Headache, unspecified) — headache and facial pain are different clinical entities

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

Is G50.9 an HCC code?

No. G50.9 is a billable ICD-10-CM code but does not map to any HCC category in V28, V24, ESRD, or RxHCC.

HCC Category Mapping

RxHCCHCC 168, Trigeminal and Postherpetic Neuralgia

0.000

RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.

MEAT Criteria for G50.9

For G50.9to 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 G50.9 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

G50.9 is the ICD-10-CM diagnosis code for disorder of trigeminal nerve, unspecified. A disorder of the trigeminal nerve where the specific type or nature of the condition is not specified or documented. G50.9 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering nerve, nerve root and plexus disorders (g50-g59).

G50.9 is a billable ICD-10-CM code but does not map to a payment HCC under the CMS-HCC V28, V24, ESRD, or RxHCC risk adjustment models. It can be reported on Medicare Advantage encounter data submissions but it does not contribute to a beneficiary's RAF score and therefore does not affect risk-adjusted payments to the plan.

Maps to RxHCC 168 (Disorders of Immunity, Nervous System Disorders) with a RAF weight of 0.000 in the prescription drug model. No mapping to CMS-HCC V28 or V24 payment models, so no direct impact on Medicare Advantage capitation. The RxHCC mapping captures pharmacy costs for anticonvulsants (carbamazepine, oxcarbazepine), muscle relaxants, and neuropathic pain medications. No hierarchies apply.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G50.9 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•This is a last-resort code; query the provider for more specific diagnosis when possible
•Avoid using this code if G50.0, G50.1, or G50.8 can be determined from documentation

Clinical Significance

Disorder of the trigeminal nerve, unspecified, is used when a trigeminal nerve condition is diagnosed but the specific type is not documented or determinable from the record. This code should prompt a query to the provider for additional specificity, as trigeminal neuralgia, atypical facial pain, and other trigeminal neuropathies require different management approaches. Unspecified codes represent missed opportunities for clinical specificity and targeted treatment.

Documentation Requirements

✓Provider documentation of a trigeminal nerve disorder (even without further specification)
✓Any available details about symptoms, distribution, or character of pain/dysfunction
✓Query opportunity: ask provider to specify type (neuralgia, neuropathy, atypical pain, other)
✓Neurological examination findings in trigeminal distribution
✓Any diagnostic workup results available

Commonly Confused Codes

•G50.0 (Trigeminal neuralgia): use when paroxysmal shock-like pain in trigeminal distribution is documented
•G50.1 (Atypical facial pain): use for continuous, poorly localized facial pain
•G50.8 (Other disorders of trigeminal nerve): use when a specific disorder is identified that is not neuralgia or atypical pain
•R51.9 (Headache, unspecified): headache and facial pain are different clinical entities
•G51.0 (Bell's palsy): facial nerve (CN VII) disorder, not trigeminal nerve (CN V)