ICD-10 Code I78 – Diseases of capillaries (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I78 – Diseases of capillaries
What it is
I78 covers noninfectious disorders of the capillaries, the smallest blood vessels. Use it when the record identifies a capillary disease but does not specify a more exact diagnosis.
Clinical signs
Clinical features vary; refer to documentation. Findings may include visible capillary abnormalities, skin discoloration, or bleeding-related changes when a capillary disorder is present.
When to use this code
Use I78 when the clinician documents a disease of capillaries without naming a specific subtype. It is appropriate for nonspecific capillary disorders in the assessment, problem list, or discharge summary. If the note identifies a more precise vascular diagnosis, code that instead.
Do not use for
Do not use this code for diseases of veins, arteries, lymphatic vessels, or blood itself. Check documentation if the condition is congenital, traumatic, or better described by another vascular code.
Coding tip
Confirm the provider actually documents a capillary disorder; if the record is vague, query or code to the most specific supported diagnosis.