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ICD-10-CM 2027 diagnosis code

G40Epilepsy and recurrent seizures

Not billable — use a more specific code

G40 is a header code, so it can't be reported by itself. Choose one of the 11 more specific codes beneath it.

Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data

About G40

G40 is the ICD-10-CM diagnosis code for epilepsy and recurrent seizures. It belongs to block G40-G47 (episodic and paroxysmal disorders) and chapter 6 (diseases of the nervous system). It is a header code, so it can't be reported by itself; one of its 11 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: G40.0 (onset), G40.1 (seizures), G40.2 (seizures), G40.3 (syndromes), G40.4 (syndromes), G40.5 (causes), G40.8 (seizures), G40.9 (unspecified) and 3 more.

Don't report G40 together with the conditions in its Excludes1 note: conversion disorder with seizures (F44.5), convulsions NOS (R56.9), post traumatic seizures (R56.1), seizure (convulsive) NOS (R56.9) and 1 more.

The conditions in its Excludes2 note aren't part of G40, but may be coded alongside it if the patient has both: hippocampal sclerosis (G93.81), mesial temporal sclerosis (G93.81), temporal sclerosis (G93.81) and Todd's paralysis (G83.84).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Specific codes under G40

Coding notes

Note
  • the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled
Excludes1Not coded here — never report together with this code
  • conversion disorder with seizures (F44.5)
  • convulsions NOS (R56.9)
  • post traumatic seizures (R56.1)
  • seizure (convulsive) NOS (R56.9)
  • seizure of newborn (P90)
Excludes2Not included here — may be reported together if both conditions exist

Notes that apply from higher levels

Instructions written at a parent level also apply to G40.

Broader instructions also apply from Chapter 6: Diseases of the nervous system.

Alphabetic index entries

2 entries

Terms in the official ICD-10-CM index that lead to G40.

Codes whose notes reference G40

Code history

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about G40

Is G40 billable?

No. G40 is a header code. Report one of its more specific subcodes instead.