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G45 ICD-10-CM Code: Transient cerebral ischemic attacks and related syndromes

ICD-10-CM Code View

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

G45

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

Transient cerebral ischemic attacks and related syndromes

Transient cerebral ischemic attacks and related syndromes

CMS-HCC V28

N/A

Not mapped

CMS-HCC V24

N/A

Not mapped

ACA/HHS

N/A

Not mapped

ESRD/PACE

N/A

Not mapped

RXHCC

N/A

Not mapped

Code Book Path

Official
G4Episodic and paroxysmal disorders (G40-G47)
G45Transient cerebral ischemic attacks and related syndromes

Inclusion Terms

Official

ICD-10-CM does not list inclusion terms for G45 in this effective period.

Excludes 2

Official

ICD-10-CM does not list Excludes 2 notes for G45 in this effective period.

Related Child Codes

Official
G45.0Vertebro-basilar artery syndrome
G45.1Carotid artery syndrome (hemispheric)
G45.2Multiple and bilateral precerebral artery syndromes
G45.3Amaurosis fugax
G45.4Transient global amnesia

Includes

Official

ICD-10-CM does not list Includes notes for G45 in this effective period.

Excludes 1

Official
  • neonatal cerebral ischemia (P91.0)
  • transient retinal artery occlusion (H34.0-)

Code First

Official

ICD-10-CM does not list Code First sequencing instructions for G45 in this effective period.

Use Additional

Official

ICD-10-CM does not list Use Additional Code instructions for G45 in this effective period.

Code Also

Official

ICD-10-CM does not list Code Also instructions for G45 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.

Coder workflow notes

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What This Code Means

G45 is the ICD-10-CM diagnosis code for transient cerebral ischemic attacks and related syndromes. G45 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 G45 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 G45'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 G45 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.

Excludes 1, Do NOT code together

  • neonatal cerebral ischemia (P91.0)
  • transient retinal artery occlusion (H34.0-)

Child Codes

Code Hierarchy

G45Transient cerebral ischemic attacks and related syndromes
G45Transient cerebral ischemic attacks and related syndromes

More on G45

Related condition guides

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