ICD-10 Code I99.8 – Other disorder of circulatory system (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I99.8 – Other disorder of circulatory system
What it is
I99.8 is used for a circulatory system disorder that does not fit a more specific ICD-10-CM code. It serves as a residual category when the documentation identifies an unusual vascular or circulatory problem.
Clinical signs
Clinical features vary; refer to documentation. Findings may reflect impaired blood flow, vascular abnormality, or other circulatory dysfunction, but the record should describe the specific condition when possible.
When to use this code
Use I99.8 when the provider documents an other or unspecified circulatory system disorder and no more specific code is available. It may apply when the condition is clearly circulatory but not indexed elsewhere. Check documentation to confirm the diagnosis and anatomic site.
Do not use for
Do not use this code if the record supports a specific vascular, cardiac, or peripheral vascular diagnosis. Avoid it when documentation is incomplete and the condition is simply unspecified.
Coding tip
Before assigning I99.8, search for a more specific circulatory diagnosis and verify the provider’s wording.