G40.319
BillableGeneralized idiopathic epilepsy and epileptic syndromes, intractable, without status epilepticus
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
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
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 G40.319 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 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