What is ICD-10 code G40.319?

G40.319 is the ICD-10-CM diagnosis code for Generalized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus. A generalized epilepsy that affects the entire brain from the start and is difficult to control with medication, but the patient is not currently in status epilepticus. G40.319 is a billable code, meaning it can be reported on a claim as a primary or secondary diagnosis when supported by documentation. G40.319 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. G40.319 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. G40.319 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 G40.319?

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 G40.319, 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 G40.319?

Document multiple failed antiepileptic drug trials to justify the intractable classification Consider noting if the patient is a candidate for surgical intervention or newer treatment options Because G40.319 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.

G40.319 ICD-10 Code: Generalized idiopathic

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 lookupG40.319Effective periodFY2026 Apr Update (Apr 1-Sep 30)

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

G40.319

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

Generalized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus

A generalized epilepsy that affects the entire brain from the start and is difficult to control with medication, but the patient is not currently in status epilepticus.

Buddy Insight

This code captures generalized idiopathic epilepsy that is drug-resistant (intractable) but without current status epilepticus.

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 163

Seizure Disorders, Intractabl...

RAF 0.0

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Code Book Path

Official

G40.3Generalized idiopathic epilepsy and epileptic syndromes

G40.31Generalized idiopathic epilepsy and epileptic syndromes, intractable

G40.319Generalized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for G40.319 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G40.319 in this effective period.

Related Child Codes

Official

G40.311Generalized idiopathic epilepsy and epileptic syndromes, intractable, with status epilepticus

Includes

Official

ICD-10-CM does not list Includes notes for G40.319 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G40.319 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G40.319 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G40.319 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G40.319 in this effective period.

Buddy Documentation Tip

HCC Buddy guidance

Documentation of generalized idiopathic epilepsy (bilateral onset, no identified cause)

Evidence of intractable status: documented failure of at least 2 adequate antiepileptic drug trials

Ongoing seizure frequency despite treatment compliance

Confirmation that patient is NOT currently in status epilepticus

MEAT Support

HCC Buddy guidance

Documentation of generalized idiopathic epilepsy (bilateral onset, no identified cause)

Evidence of intractable status: documented failure of at least 2 adequate antiepileptic drug trials

Ongoing seizure frequency despite treatment compliance

Confirmation that patient is NOT currently in status epilepticus

Audit Caution

HCC Buddy guidance

Using 'not intractable' codes when multiple medications have failed

Not documenting specific medications tried, doses, and reasons for discontinuation

Confusing medication intolerance (side effects) with true intractability (seizures continue despite adequate drug levels)

Failing to update the code if new treatment achieves seizure control, changing status from intractable to not intractable

Common Mistakes

HCC Buddy guidance

G40.309 — Same type, NOT intractable; medication responsive

G40.311 — Same type, intractable, WITH status epilepticus; acute emergency

G40.019 — FOCAL idiopathic epilepsy, intractable; focal onset pattern

G40.419 — Other generalized epilepsy, intractable; different etiology classification

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 G40.319 an HCC code?

Yes. G40.319 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 163, Seizure Disorders, 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 G40.319

For G40.319to 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 G40.319 during that encounter, not just copy-forwarded from a problem list.

What This Code Means

G40.319 is the ICD-10-CM diagnosis code for generalized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus. A generalized epilepsy that affects the entire brain from the start and is difficult to control with medication, but the patient is not currently in status epilepticus. G40.319 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, G40.319 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, G40.319 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.

Document multiple failed antiepileptic drug trials to justify the intractable classification. Because G40.319 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 G40.319 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Coding Tips

•Document multiple failed antiepileptic drug trials to justify the intractable classification
•Consider noting if the patient is a candidate for surgical intervention or newer treatment options

Clinical Significance

This code captures generalized idiopathic epilepsy that is drug-resistant (intractable) but without current status epilepticus. These patients have ongoing generalized seizures despite adequate medication trials. They represent a population with significant ongoing care needs and may be candidates for advanced interventions such as vagus nerve stimulation, responsive neurostimulation, or dietary therapies.

Documentation Requirements

✓Documentation of generalized idiopathic epilepsy (bilateral onset, no identified cause)
✓Evidence of intractable status: documented failure of at least 2 adequate antiepileptic drug trials
✓Ongoing seizure frequency despite treatment compliance
✓Confirmation that patient is NOT currently in status epilepticus
✓Documentation of current and failed medication regimens
✓Assessment for advanced treatment options (neurostimulation, dietary therapy, clinical trials)

Commonly Confused Codes

•G40.309 — Same type, NOT intractable; medication responsive
•G40.311 — Same type, intractable, WITH status epilepticus; acute emergency
•G40.019 — FOCAL idiopathic epilepsy, intractable; focal onset pattern
•G40.419 — Other generalized epilepsy, intractable; different etiology classification
•G40.919 — Epilepsy unspecified, intractable; less specific