Is G45 a billable ICD-10-CM code?

No. G45 is a non-billable header code. Code to a higher level of specificity using one of its child codes.

Where does G45 sit in the tabular list?

Diseases of the nervous system (G00-G99), in the block Episodic and paroxysmal disorders (G40-G47).

What cannot be coded together with G45?

G45 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.

G45

G45 — Transient cerebral ischemic attacks and related syndromes

Non-billable headerICD-10-CM

G45 is a non-billable header ICD-10-CM code for transient cerebral ischemic attacks and related syndromes. It cannot be billed on its own: choose one of the more specific child codes below.

Excludes1 — never code together

These conditions cannot occur together. Billing both on the same encounter is a denial.

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

Other codes that can never be billed with G45

These codes carry an Excludes1 note pointing at G45. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading G45 alone.

R29.5Transient paralysis
R41.3Other amnesia
H34Retinal vascular occlusions
H53.12Transient visual loss
H54Blindness and low vision
I65Occlusion and stenosis of precerebral arteries, not resulting in cerebral infarction

Risk adjustment

G45 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.

Code to one of these instead G45

7 child codes. Green means billable.

Questions about G45

Is G45 a billable ICD-10-CM code?: No. G45 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
Where does G45 sit in the tabular list?: Diseases of the nervous system (G00-G99), in the block Episodic and paroxysmal disorders (G40-G47).
What cannot be coded together with G45?: G45 carries an Excludes1 note, which means the conditions it lists can never be coded together with it on the same encounter.