Non-Billable / Non-Specific Code
ICD-10-CM I66 is the diagnosis code for Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction. This code falls under the section "Cerebrovascular diseases" within Chapter 9 — Diseases of the circulatory system (I00-I99). It is a non-billable/non-specific ICD-10-CM code that should not be used for reimbursement. A more specific sub-code is required for billing. Medical coders and healthcare providers use this code to document and classify diagnoses in electronic health records, insurance claims, and clinical databases.
The following conditions should never be coded at the same time as I66. They are mutually exclusive:
Understanding where I66 sits in the ICD-10-CM classification helps ensure proper coding:
No, I66 is a non-billable/non-specific code. You should use a more specific sub-code for billing and reimbursement.
I66 is the ICD-10-CM diagnosis code for "Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction". It is used by healthcare providers to classify and document this condition in medical records and insurance claims.
I66 is located in Section I60-I69 — "Cerebrovascular diseases" within Chapter 9 of the ICD-10-CM Tabular List.
I66 has 6 sub-code(s) that provide more specific detail: I66.0, I66.1, I66.2, I66.3, I66.8 and more.
Use I66 when the patients documented diagnosis matches "Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction" and the clinical documentation supports this level of specificity. Always verify with the latest ICD-10-CM guidelines and payer requirements.
The ICD-10-CM code for Occlusion and stenosis of cerebral arteries, not resulting in cerebral infarction is I66.
No, I66 is non-billable. Use a more specific sub-code for primary diagnosis billing.
I66 is in Chapter 9 of the ICD-10-CM Tabular List.
Type 1 Excludes for I66 include: Occlusion and stenosis of cerebral artery causing cerebral infarction (I63.3-I63.5).
Yes, I66 is a valid ICD-10-CM code for the 2026 fiscal year, subject to official CMS updates.