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G40.90 ICD-10-CM Code: Epilepsy, unspecified, not intractable

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FY 2026 Apr update / Diseases of the nervous system (G00-G99) / Episodic and paroxysmal disorders (G40-G47)

G40.90

Header CodeICD-10-CMOfficial ICD-10-CMCodebook guidance

Epilepsy, unspecified, not intractable

Epilepsy, unspecified, not intractable

CMS-HCC V28

0

0

RAF 0

CMS-HCC V24

0

0

RAF 0

ACA/HHS

0

0

RAF 0

ESRD/PACE

0

0

RAF 0

RXHCC

0

0

RAF 0

Code Trumping

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Code Book Path

Official
G40Epilepsy and recurrent seizures
G40.9Epilepsy, unspecified
G40.90Epilepsy, unspecified, not intractable

Inclusion Terms

Official
  • Epilepsy, unspecified, without intractability

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G40.90 in this effective period.

Related Child Codes

Official
G40.901Epilepsy, unspecified, not intractable, with status epilepticus
G40.909Epilepsy, unspecified, not intractable, without status epilepticus

Includes

Official

ICD-10-CM does not list Includes notes for G40.90 in this effective period.

Excludes 1

Official

ICD-10-CM does not list Excludes 1 notes for G40.90 in this effective period.

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G40.90 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G40.90 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G40.90 in this effective period.

Last updated: FY2026 ICD-10-CM Apr update, Apr 1, 2026 through Sep 30, 2026. CMS-HCC V28 is 100% phased in for payment year 2026.

What This Code Means

G40.90 is the ICD-10-CM diagnosis code for epilepsy, unspecified, not intractable. G40.90 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).

Header codes like G40.90 cannot be reported on claims directly, they organize child codes that share clinical context but the actual diagnosis must be coded to the highest level of specificity supported by the documentation. Coders should look at G40.90's child codes and select the one that matches the patient's documented presentation, since payers reject header codes submitted as the primary diagnosis. For risk adjustment workflows, header codes never contribute to a Medicare Advantage member's RAF score on their own; only billable child codes that happen to map to a payment HCC affect risk-adjusted plan payments.

HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for G40.90 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Child Codes

Code Hierarchy

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