I66.9
Billable

Occlusion and stenosis of unspecified cerebral artery

Billable / Specific Code

What is Occlusion and stenosis of unspecified cerebral artery?

ICD-10-CM I66.9 is the diagnosis code for Occlusion and stenosis of unspecified cerebral artery. This code falls under the section "Cerebrovascular diseases" within Chapter 9 — Diseases of the circulatory system (I00-I99). It is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.

Coding Guidelines for I66.9

Always refer to the official ICD-10-CM Tabular List for complete coding guidelines. Ensure documentation supports the specificity of the code selected. When in doubt, consult a certified medical coder or the latest CMS guidelines.

ICD-10-CM Code Hierarchy

Understanding where I66.9 sits in the ICD-10-CM classification helps ensure proper coding:

Related Codes

Frequently Asked Questions

Is I66.9 a billable ICD-10-CM code?

Yes, I66.9 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.

What does I66.9 mean?

I66.9 is the ICD-10-CM diagnosis code for "Occlusion and stenosis of unspecified cerebral artery". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.

What is the parent code of I66.9?

The parent code of I66.9 is I66 ("Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction"). I66.9 provides a more specific classification within this category.

What section is I66.9 in?

I66.9 is located in Section I60-I69 — "Cerebrovascular diseases" within Chapter 9 of the ICD-10-CM Tabular List.

When should I use I66.9?

Use I66.9 when the patients documented diagnosis matches "Occlusion and stenosis of unspecified cerebral artery" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.

People Also Ask

What is the ICD-10 code for Occlusion and stenosis of unspecified cerebral artery?

The ICD-10-CM code for Occlusion and stenosis of unspecified cerebral artery is I66.9.

Can I66.9 be used for primary diagnosis?

Yes, I66.9 can be used as a primary diagnosis code since it is billable and specific.

What chapter is I66.9 in?

I66.9 is in Chapter 9 of the ICD-10-CM Tabular List.

Is I66.9 valid for 2026?

Yes, I66.9 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.

See Also

← PreviousI66.8Occlusion and stenosis of other cerebral arteriesNext →I67Other cerebrovascular diseases
Code Details
I66.9
Occlusion and stenosis of unspecified cerebral artery
Billable / Specific Code
9 — Diseases of the circulatory system (I00-I99)
I60-I69 — Cerebrovascular diseases
2026 ICD-10-CM