G45.9 Transient cerebral ischemic attack, unspecified

The ICD-10-CM code for Transient cerebral ischemic attack, unspecified is G45.9 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

6: Diseases of the nervous system (G00-G99)

Section

G40-G47: Episodic and paroxysmal disorders (G40-G47)

Category G45

8 codes (7 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to G45.9:

• Spasm (s), spastic, spasticity › cerebral (arteries) (vascular)
• Angiospasm (peripheral) (traumatic) (vessel) › cerebral
• Claudication (intermittent) › cerebral (artery)
• Attack, attacks › transient ischemic (TIA)
• Ischemia, ischemic › cerebral (chronic) (generalized) › transient
• Spasm (s), spastic, spasticity › artery › cerebral
• Ischemia, ischemic › cerebral (chronic) (generalized) › intermittent
• Disease, diseased › angiospastic › cerebral

Inclusion Terms

• Spasm of cerebral artery
• TIA
• Transient cerebral ischemia NOS

U.S. Hospital Utilization

• An estimated 125,125 U.S. inpatient stays in 2023 included G45.9 among the documented diagnoses.
• 79,740 stays listed it as the principal diagnosis.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

Dominant/nondominant side (TOC entry)

a. Dominant/nondominant side ................................................................................................. 45

Pain - Category G89 (TOC entry)

b. Pain - Category G89.............................................................................................................. 45

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)