ICD-10 Code I80.9 – Phlebitis and thrombophlebitis of unspecified site (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I80.9 – Phlebitis and thrombophlebitis of unspecified site
What it is
This code identifies inflammation of a vein with clot formation when the site is not specified in the record. Use it only when documentation confirms phlebitis or thrombophlebitis but does not name the affected vein.
Clinical signs
Typical findings include localized pain, tenderness, swelling, redness, or warmth along a vein. Clinical features vary; refer to documentation, and code only when the provider documents phlebitis or thrombophlebitis.
When to use this code
Use I80.9 when the diagnosis is clearly stated but the chart does not identify a specific limb or vein. It may also fit when the provider documents thrombophlebitis without further detail. If another site is named, choose the more specific code instead.
Do not use for
Do not use this code for superficial injury, cellulitis, or edema without documented phlebitis or thrombophlebitis. Check documentation if the record names a specific vein, because a more precise code may apply.
Coding tip
Query or review the note for vein location before defaulting to I80.9.