What is ICD-10 code G40.401?

G40.401 is the ICD-10-CM diagnosis code for Other generalized epilepsy and epileptic syndromes, not intractable, with status epilepticus. A generalized epilepsy of a type other than idiopathic that is controllable with medication, but the patient is currently experiencing status epilepticus. G40.401 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G40.401 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. G40.401 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. G40.401 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 G40.401?

CMS phased in the V28 risk adjustment model over payment years 2024 (33%), 2025 (67%), and 2026 (100%), replacing V24. V28 consolidates HCC categories, removes some lower-acuity conditions, and recalibrates RAF weights across the entire model. For G40.401, V28 maps to Seizure Disorders and Convulsions at RAF 0.262 while V24 mapped to Seizure Disorders and Convulsions at RAF 0.244. Both models can still appear in legacy data and in payer-specific lookback periods.

What should coders know when reporting G40.401?

The '4' in the fourth character indicates 'other' generalized epilepsy, which may have a secondary cause that should be documented Identify and document the underlying cause (e.g., brain injury, infection, tumor) if known Because G40.401 maps to a payment HCC, the documentation must also satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's risk adjustment score.

G40.401 ICD-10 Code: Other generalized epilepsy

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 lookupG40.401Effective periodFY2026 Apr Update (Apr 1-Sep 30)

FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Episodic and paroxysmal disorders (G40-G47)

G40.401

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

Other generalized epilepsy and epileptic syndromes, not intractable, with status epilepticus

A generalized epilepsy of a type other than idiopathic that is controllable with medication, but the patient is currently experiencing status epilepticus.

Buddy Insight

Other generalized epilepsy with status epilepticus represents a neurological emergency where seizures involve both brain hemispheres and persist beyond 5 minutes or recur without recovery.

CMS-HCC V28

Mapped

HCC 201

Seizure Disorders and Convuls...

RAF 0.262

CMS-HCC V24

Mapped

HCC 79

Seizure Disorders and Convuls...

RAF 0.244

ACA/HHS

Not risk-adjusted for this model/period.

RAF 0

ESRD/PACE

Mapped

HCC 79

Seizure Disorders and Convuls...

RAF 0.0

RXHCC

Mapped

HCC 164

Seizure Disorders, Non-Intrac...

RAF 0.0

Code Trumping

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Code Book Path

Official

G40.4Other generalized epilepsy and epileptic syndromes

G40.40Other generalized epilepsy and epileptic syndromes, not intractable

G40.401Other generalized epilepsy and epileptic syndromes, not intractable, with status epilepticus

Inclusion Terms

Official

Other generalized epilepsy and epileptic syndromes without intractability
Other generalized epilepsy and epileptic syndromes NOS

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G40.401 in this effective period.

Related Child Codes

Official

G40.409Other generalized epilepsy and epileptic syndromes, not intractable, without status epilepticus

Includes

Official

ICD-10-CM does not list Includes notes for G40.401 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G40.401 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G40.401 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G40.401 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G40.401 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Specific type of generalized epilepsy documented (e.g., secondary to brain injury, infection, or tumor)

Statement confirming seizures are NOT intractable/drug-resistant (responsive to medication)

Documentation of active status epilepticus during the encounter (seizure duration >5 minutes or recurrent seizures without recovery)

Current antiepileptic drug regimen with dosages

MEAT Support

HCC Buddy guidance

Specific type of generalized epilepsy documented (e.g., secondary to brain injury, infection, or tumor)

Statement confirming seizures are NOT intractable/drug-resistant (responsive to medication)

Documentation of active status epilepticus during the encounter (seizure duration >5 minutes or recurrent seizures without recovery)

Current antiepileptic drug regimen with dosages

Audit Caution

HCC Buddy guidance

Coding status epilepticus when documentation only mentions a single brief seizure — status epilepticus requires seizures lasting >5 minutes or recurrent seizures without full recovery between episodes

Using this code when documentation indicates drug-resistant or intractable epilepsy — intractable forms require G40.411

Failing to identify the specific generalized epilepsy subtype when documentation supports a more specific code like Lennox-Gastaut (G40.811) or absence epilepsy (G40.A01)

Assigning this code based on history of status epilepticus rather than current encounter documentation

Common Mistakes

HCC Buddy guidance

G40.409 — Same epilepsy type, not intractable, but WITHOUT status epilepticus; use when patient is not in prolonged seizure state

G40.411 — Same epilepsy type WITH status epilepticus but INTRACTABLE (drug-resistant); requires documentation of failed medication trials

G40.301 — Generalized IDIOPATHIC epilepsy with status epilepticus; use when epilepsy has no identified secondary cause

G40.901 — Epilepsy UNSPECIFIED with status epilepticus; use only when epilepsy type cannot be determined

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 G40.401 an HCC code?

Yes. G40.401 maps to Seizure Disorders and Convulsions under the CMS-HCC V28 risk adjustment model (and Seizure Disorders and Convulsions under V24).

HCC Category Mapping

V28HCC 201, Seizure Disorders and Convulsions

0.262

V24HCC 79, Seizure Disorders and Convulsions

0.244

ESRDHCC 79, Seizure Disorders and Convulsions

0.000

RxHCCHCC 164, Seizure Disorders, Non-Intractable Epilepsy

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 G40.401

For G40.401to 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 G40.401 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

G40.401 is the ICD-10-CM diagnosis code for other generalized epilepsy and epileptic syndromes, not intractable, with status epilepticus. A generalized epilepsy of a type other than idiopathic that is controllable with medication, but the patient is currently experiencing status epilepticus. G40.401 sits in the ICD-10-CM chapter for diseases of the nervous system (g00-g99), within the section covering episodic and paroxysmal disorders (g40-g47).

Under the CMS-HCC V28 risk adjustment model, G40.401 maps to Seizure Disorders and Convulsions (HCC 201) with a community, non-dual, aged base RAF weight of 0.262. Under the older V24 model, G40.401 mapped to the same category but with a base RAF weight of 0.244, V28 recalibrated weights across the entire model. 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.

The '4' in the fourth character indicates 'other' generalized epilepsy, which may have a secondary cause that should be documented. Because G40.401 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. 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, RAF weights, and MEAT documentation criteria for G40.401 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•The '4' in the fourth character indicates 'other' generalized epilepsy, which may have a secondary cause that should be documented
•Identify and document the underlying cause (e.g., brain injury, infection, tumor) if known

Clinical Significance

Other generalized epilepsy with status epilepticus represents a neurological emergency where seizures involve both brain hemispheres and persist beyond 5 minutes or recur without recovery. This diagnosis drives significant resource utilization for emergency management including IV benzodiazepines, continuous EEG monitoring, and potential ICU admission. Accurate capture is critical for risk adjustment as it reflects a patient with higher-than-average healthcare needs.

Documentation Requirements

✓Specific type of generalized epilepsy documented (e.g., secondary to brain injury, infection, or tumor)
✓Statement confirming seizures are NOT intractable/drug-resistant (responsive to medication)
✓Documentation of active status epilepticus during the encounter (seizure duration >5 minutes or recurrent seizures without recovery)
✓Current antiepileptic drug regimen with dosages
✓Emergency interventions provided for status epilepticus
✓Underlying etiology if known (structural, metabolic, genetic)

Commonly Confused Codes

•G40.409 — Same epilepsy type, not intractable, but WITHOUT status epilepticus; use when patient is not in prolonged seizure state
•G40.411 — Same epilepsy type WITH status epilepticus but INTRACTABLE (drug-resistant); requires documentation of failed medication trials
•G40.301 — Generalized IDIOPATHIC epilepsy with status epilepticus; use when epilepsy has no identified secondary cause
•G40.901 — Epilepsy UNSPECIFIED with status epilepticus; use only when epilepsy type cannot be determined
•G40.801 — Other epilepsy (not fitting specific syndromes) with status epilepticus; less specific than G40.4 series