G40.019 ICD-10-CM Code: Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, without status epilepticus
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FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Episodic and paroxysmal disorders (G40-G47)
G40.019
Billable / SpecificICD-10-CMOfficial ICD-10-CMCodebook guidanceLocalization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, without status epilepticus
This is a type of epilepsy that starts in a specific area of the brain and cannot be controlled with medication. The person experiences seizures that begin in one location but the condition is difficult to treat.
Buddy Insight
This code captures focal idiopathic epilepsy that is drug-resistant (intractable) but the patient is not currently in status epilepticus.
CMS-HCC V28
MappedHCC 201
RAF 0.262
CMS-HCC V24
MappedHCC 79
RAF 0.244
ACA/HHS
00
RAF 0
ESRD/PACE
MappedHCC 79
RAF 0.0
RXHCC
MappedHCC 163
RAF 0.0
Code Trumping
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Code Book Path
Inclusion Terms
OfficialICD-10-CM does not list inclusion terms for G40.019 in this effective period.
Excludes 2
OfficialICD-10-CM does not list Excludes 2 notes for G40.019 in this effective period.
Related Child Codes
Includes
OfficialICD-10-CM does not list Includes notes for G40.019 in this effective period.
Excludes 1
OfficialICD-10-CM does not list Excludes 1 notes for G40.019 in this effective period.
Code First
OfficialICD-10-CM does not list Code First sequencing instructions for G40.019 in this effective period.
Use Additional
OfficialICD-10-CM does not list Use Additional Code instructions for G40.019 in this effective period.
Code Also
OfficialICD-10-CM does not list Code Also instructions for G40.019 in this effective period.
Buddy Documentation Tip
MEAT Support
Audit Caution
Common Mistakes
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 G40.019 an HCC code?
Yes. G40.019 maps to Seizure Disorders and Convulsions under the CMS-HCC V28 risk adjustment model (and Seizure Disorders and Convulsions under V24).
HCC Category Mapping
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 G40.019
For G40.019to 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 G40.019 during that encounter, not just copy-forwarded from a problem list.
What This Code Means
G40.019 is the ICD-10-CM diagnosis code for localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable, without status epilepticus. This is a type of epilepsy that starts in a specific area of the brain and cannot be controlled with medication. The person experiences seizures that begin in one location but the condition is difficult to treat. G40.019 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, G40.019 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, G40.019 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.
Verify documentation confirms the epilepsy is idiopathic (no known cause), localization-related, and intractable (drug-resistant) before assigning this code. Because G40.019 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 G40.019 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •Verify documentation confirms the epilepsy is idiopathic (no known cause), localization-related, and intractable (drug-resistant) before assigning this code
- •Ensure the documentation explicitly states 'without status epilepticus' or does not mention status epilepticus; if status epilepticus is present, use G40.011 instead
Clinical Significance
This code captures focal idiopathic epilepsy that is drug-resistant (intractable) but the patient is not currently in status epilepticus. It identifies patients whose seizures continue despite adequate medication trials, indicating higher baseline complexity and ongoing management challenges. These patients may be candidates for epilepsy surgery or neuromodulation devices.
Documentation Requirements
- ✓Documentation confirming focal (localization-related) idiopathic epilepsy
- ✓Documentation of intractable status including failed medication trials
- ✓List of antiepileptic medications tried and reasons for failure or switching
- ✓Current seizure frequency and types
- ✓Confirmation that patient is NOT currently in status epilepticus
- ✓Evaluation for surgical candidacy or other advanced interventions if applicable
Commonly Confused Codes
- •G40.009 — Same type, NOT intractable, without status epilepticus; well-controlled version
- •G40.011 — Same type, intractable, WITH status epilepticus; acute emergency presentation
- •G40.119 — Symptomatic focal epilepsy, intractable; has an identified structural cause
- •G40.319 — Generalized idiopathic epilepsy, intractable; generalized rather than focal onset
- •G40.919 — Epilepsy unspecified, intractable; less specific