I66
⚠ Non-billable
Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction
ICD-10-CM · FY2026 · Diseases of the Circulatory System
Code
I66
System
ICD-10-CM
Billable
No — use specific code
Effective
FY2026
Chapter
Diseases of the Circulatory System
Source
CMS / CDC NCHS
⚠ Verify before billing. Confirm against the current CMS/NCHS ICD-10-CM files and your payer's rules before claims submission.
Frequently asked questions
What is ICD-10 code I66?
ICD-10-CM code I66 represents Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction. It is a non-billable header code requiring a more specific subcategory in the Diseases of the Circulatory System chapter, effective October 1, 2025 – September 30, 2026.
Is I66 billable?
No. I66 is a non-billable header. Select a more specific subcategory for claims submission.
What chapter is I66 in?
I66 belongs to the Diseases of the Circulatory System chapter (I00–I99) of ICD-10-CM.
Related codes in the I66 category
I66.0
Occlusion and stenosis of middle cerebral artery
Non-billable
I66.1
Occlusion and stenosis of anterior cerebral artery
Non-billable
I66.2
Occlusion and stenosis of posterior cerebral artery
Non-billable
I66.3
Occlusion and stenosis of cerebellar arteries
Billable
I66.8
Occlusion and stenosis of other cerebral arteries
Billable
I66.9
Occlusion and stenosis of unspecified cerebral artery
Billable
I66.01
Occlusion and stenosis of right middle cerebral artery
Billable
I66.02
Occlusion and stenosis of left middle cerebral artery
Billable
Search all 98,186 ICD-10-CM codes instantly
Search ICDwise →