ICD-10 Code I80 – Phlebitis and thrombophlebitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I80 – Phlebitis and thrombophlebitis
What it is
I80 refers to inflammation of a vein with associated clot formation, usually in a superficial or deep vein. Use it when the record documents phlebitis, thrombophlebitis, or both.
Clinical signs
Common findings include localized pain, tenderness, warmth, redness, and swelling along a vein. Clinical features vary; refer to documentation for the vein involved and whether the process is superficial or deep.
When to use this code
Use I80 when the provider clearly diagnoses phlebitis or thrombophlebitis and does not specify a more detailed site or laterality that requires a different code. It may also fit documented vein inflammation with thrombus formation. Check documentation for acute versus chronic wording and any related complications.
Do not use for
Do not use I80 for uncomplicated edema, cellulitis, or nonspecific leg pain without documentation of vein inflammation or thrombosis. If the record names a different vascular disorder, code that condition instead.
Coding tip
Capture the exact vein, site, and acuity from the note before assigning the code.