ICD-10-CM 2027
ICD-10 code for Lennox-Gastaut syndrome
Lennox-Gastaut syndrome, not intractable, without status epilepticus
From the official ICD-10-CM alphabetic index entry “Lennox-Gastaut syndrome”. Page updated September 29, 2026.
About coding Lennox-Gastaut syndrome
The ICD-10-CM code for Lennox-Gastaut syndrome is G40.812 (Lennox-Gastaut syndrome, not intractable, without status epilepticus). The official index lists 6 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on G40.812.
Within G40.81, choose G40.812 (not intractable, without status epilepticus) only when documentation doesn't support a more specific option: not intractable, with status epilepticus (G40.811), intractable, with status epilepticus (G40.813) and intractable, without status epilepticus (G40.814).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
In MS-DRG v44.0, it is part of the grouping logic for DRG 023 (Craniotomy with Major Device Implant or Acute Complex CNS Principal Diagnosis with MCC or Antineoplastic Implant or Epilepsy with Neurostimulator, relative weight 5.7444), DRG 100 (Seizures with MCC, relative weight 1.9233) and DRG 101 (Seizures without MCC, relative weight 0.8952), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific Lennox-Gastaut syndrome codes (official index)
- intractable G40.814 — Lennox-Gastaut syndrome, intractable, without status epilepticus
- with status epilepticus G40.813 — Lennox-Gastaut syndrome, intractable, with status epilepticus
- without status epilepticus G40.814 — Lennox-Gastaut syndrome, intractable, without status epilepticus
- not intractable G40.812 — Lennox-Gastaut syndrome, not intractable, without status epilepticus
- with status epilepticus G40.811 — Lennox-Gastaut syndrome, not intractable, with status epilepticus
- without status epilepticus G40.812 — Lennox-Gastaut syndrome, not intractable, without status epilepticus
Common questions about Lennox-Gastaut syndrome ICD-10 codes
What is the ICD-10 code for Lennox-Gastaut syndrome?
- G40.812 — Lennox-Gastaut syndrome, not intractable, without status epilepticus. More specific codes apply when the documentation supports them: G40.814, G40.813, G40.814, G40.812 and others below.
What is the ICD-10 code for intractable lennox-gastaut syndrome?
- G40.814 — Lennox-Gastaut syndrome, intractable, without status epilepticus.
Is G40.812 billable?
- Yes. G40.812 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can G40.812 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict G40.812 as a principal diagnosis.
Is G40.812 a CC or MCC?
- G40.812 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.