2027 ICD-10-CM Diagnosis Code G40Epilepsy and recurrent seizures

ICD-10-CM Codes›G00–G99›G40-G47›G40

ICD-10-CM G40
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

G40 is a non-billable ICD-10-CM category code for epilepsy and recurrent seizures, so it cannot be submitted on claims. Use a more specific code from this category instead, such as G40.001, G40.009, G40.011, and G40.019.

Code Identity

ICD-10-CM Code
G40
Billable Status
No — Non-Billable Category
Code Describes
Epilepsy and recurrent seizures
Short Description
Epilepsy and recurrent seizures
Same as the full description in the CMS dataset.
Chapter
G40-G47
Episodic and paroxysmal disorders

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG40-G47Episodic and paroxysmal disorders
CategoryG40Epilepsy and recurrent seizures
This CodeG40Epilepsy and recurrent seizures

Specific Coding for Epilepsy and recurrent seizuresOverview

Non-specific codes like G40 require more characters. Use one of these billable codes instead:

  • G40.0 for Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset

  • G40.00 for Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, not intractable

  • G40.01 for Localization-related (focal) (partial) idiopathic epilepsy and epileptic syndromes with seizures of localized onset, intractable

  • G40.1 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures

  • G40.10 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, not intractable

  • G40.11 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with simple partial seizures, intractable

  • G40.2 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures

  • G40.20 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, not intractable

  • G40.21 for Localization-related (focal) (partial) symptomatic epilepsy and epileptic syndromes with complex partial seizures, intractable

  • G40.3 for Generalized idiopathic epilepsy and epileptic syndromes

  • G40.30 for Generalized idiopathic epilepsy and epileptic syndromes, not intractable

  • G40.31 for Generalized idiopathic epilepsy and epileptic syndromes, intractable

  • G40.4 for Other generalized epilepsy and epileptic syndromes

  • G40.40 for Other generalized epilepsy and epileptic syndromes, not intractable

  • G40.41 for Other generalized epilepsy and epileptic syndromes, intractable

  • Use G40.42 for Cyclin-Dependent Kinase-Like 5 Deficiency Disorder

  • G40.5 for Epileptic seizures related to external causes

  • G40.50 for Epileptic seizures related to external causes, not intractable

  • G40.8 for Other epilepsy and recurrent seizures

  • G40.80 for Other epilepsy

  • G40.81 for Lennox-Gastaut syndrome

  • G40.82 for Epileptic spasms

  • G40.83 for Dravet syndrome

  • G40.84 for KCNQ2-related epilepsy

  • Use G40.89 for Other seizures

  • G40.9 for Epilepsy, unspecified

  • G40.90 for Epilepsy, unspecified, not intractable

  • G40.91 for Epilepsy, unspecified, intractable

  • G40.A for Absence epileptic syndrome

  • G40.A0 for Absence epileptic syndrome, not intractable

  • G40.A1 for Absence epileptic syndrome, intractable

  • G40.B for Juvenile myoclonic epilepsy [impulsive petit mal]

  • G40.B0 for Juvenile myoclonic epilepsy, not intractable

  • G40.B1 for Juvenile myoclonic epilepsy, intractable

  • G40.C for Lafora progressive myoclonus epilepsy

  • G40.C0 for Lafora progressive myoclonus epilepsy, not intractable

  • G40.C1 for Lafora progressive myoclonus epilepsy, intractable

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to G40: its own notes plus those printed at Chapter 6. A note printed at a category, block or chapter applies to every code under it.

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

  • conversion disorder with seizures (F44.5)
  • convulsions NOS (R56.9)
  • post traumatic seizures (R56.1)
  • seizure (convulsive) NOS (R56.9)
  • seizure of newborn (P90)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

On G40 itself
From Chapter 6 (G00-G99) Diseases of the nervous system applies to 700 codes
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • injury, poisoning and certain other consequences of external causes (S00-T88)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)

Notes

General instructions on how these codes are used.

  • the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name G40, its category, or a range that includes it.

Excludes1 3

These codes carry an Excludes1 note naming G40: they are not reported together with it, unless the two conditions are unrelated.

  • G25.3 Myoclonus
    myoclonic epilepsy (G40.-)
  • R56 Convulsions, not elsewhere classified
    epileptic convulsions and seizures (G40.-)
  • R56.1 Post traumatic seizures
    post traumatic epilepsy (G40.-)

Excludes2 2

These codes carry an Excludes2 note naming G40: its condition is not part of those codes, and both may be reported when the patient has both.

  • F44.0 Dissociative amnesia
    postictal amnesia in epilepsy (G40.-)
  • F44.1 Dissociative fugue
    postictal fugue in epilepsy (G40.-)

Code First 1

These codes say to code first a condition named in the note, and G40 is one of the conditions named.

  • F02 Dementia in other diseases classified elsewhere
    epilepsy and recurrent seizures (G40.-)

Use Additional Code 2

These codes say to use an additional code from the note, and G40 is one of the codes named.

  • Q87.87 Hao-Fountain Syndrome
    epilepsy, by specific type (G40.-)
  • Q93.52 Phelan-McDermid syndrome
    epilepsy and recurrent seizures (G40.-)

Code Also 10

These codes say G40 may also be needed to fully describe the condition. The note gives no sequencing direction.

  • E20.810 Autosomal dominant hypocalcemia
    seizure disorder (G40.-, R56.9)
  • F78.A1 SYNGAP1-related intellectual disability
    epilepsy and recurrent seizures (G40.-)
  • G04.8 Other encephalitis, myelitis and encephalomyelitis
    any associated seizure (G40.-, R56.9)
  • G40.5 Epileptic seizures related to external causes
    if applicable, associated epilepsy and recurrent seizures (G40.-)
  • G43.1 Migraine with aura
    any associated seizure (G40.-, R56.9)
  • G93.45 Developmental and epileptic encephalopathy
    epilepsy, by specific type (G40.-)
  • I67.850 Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
    epilepsy (G40.-)
  • Q87.85 MED13L syndrome
    epilepsy and recurrent seizures (G40.-)
  • QA0 Neurodevelopmental disorders related to specific genetic pathogenic variants
    epilepsy, by specific type (G40.-)
  • Z15.1 Genetic susceptibility to epilepsy and neurodevelopmental disorders
    epilepsy, by specific type (G40.-)

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

Patient EducationClinical

Epilepsy

Epilepsy is a brain disorder that causes people to have recurring seizures. The seizures happen when clusters of nerve cells, or neurons, in the brain send out the wrong signals. People may have strange sensations and emotions or behave strangely. They may have violent muscle spasms or lose consciousness.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About G40Overview

What is the ICD-10 code for epilepsy and recurrent seizures?

G40 is the ICD-10-CM category for epilepsy and recurrent seizures, but it is a non-billable header: claims need a more specific code from this category, listed on this page.

Is G40 (Epilepsy and recurrent seizures) a billable code?

No. This is a category header that groups the codes for epilepsy and recurrent seizures, and headers cannot be submitted on claims. Claims for epilepsy and recurrent seizures need a more specific code from this category, such as G40.001, G40.009, and G40.011.

Can G40 be reported with F44.5?

Not as a rule. The Excludes1 note on G40 lists "conversion disorder with seizures (F44.5)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).