G40.101
BillableLocalization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, with status epilepticus
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is G40.101 an HCC code?
Yes. G40.101 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 G40.101
For G40.101 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 G40.101 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
G40.101 is the ICD-10-CM diagnosis code for localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable, with status epilepticus. A type of epilepsy caused by a known brain condition with simple partial seizures (affecting one area of the brain) that responds to medication, and the patient is currently experiencing prolonged seizure activity. G40.101 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, G40.101 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, G40.101 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 '10' indicates symptomatic (known cause) with simple partial seizures; the final '1' indicates status epilepticus is present. Because G40.101 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 G40.101 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
- •The '10' indicates symptomatic (known cause) with simple partial seizures; the final '1' indicates status epilepticus is present
- •Document the underlying cause of the epilepsy (e.g., brain injury, stroke, tumor) to support medical necessity
Clinical Significance
This code captures symptomatic focal epilepsy with simple partial seizures (consciousness preserved) that is medication-responsive but with current status epilepticus. The 'symptomatic' designation means there is an identifiable cause (brain injury, stroke, tumor). Status epilepticus in this context is a medical emergency requiring immediate treatment.
Documentation Requirements
- ✓Documentation of focal epilepsy with identified structural or metabolic cause
- ✓Documentation that seizures are simple partial (consciousness preserved during seizures)
- ✓Active status epilepticus with onset time and emergency treatment
- ✓Identification of the underlying cause (prior stroke, brain tumor, traumatic brain injury, etc.)
- ✓Statement that the epilepsy is generally not intractable (medication responsive)
- ✓EEG findings and neuroimaging documenting the structural lesion
Commonly Confused Codes
- •G40.001 — Idiopathic focal epilepsy with status epilepticus; no identified cause vs. symptomatic
- •G40.109 — Same type WITHOUT status epilepticus; the stable baseline version
- •G40.201 — Symptomatic focal epilepsy with COMPLEX partial seizures and status epilepticus; impaired consciousness
- •G40.111 — Same type, intractable, with status epilepticus; drug-resistant version
- •G40.301 — Generalized idiopathic epilepsy with status epilepticus; generalized onset