ICD-10 Code I80.3 – Phlebitis and thrombophlebitis of lower extremities, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I80.3 – Phlebitis and thrombophlebitis of lower extremities, unspecified
What it is
I80.3 identifies inflammation of a vein in the lower extremity with or without associated clot, when the record does not specify a more exact site or type. Use it when the documentation only says phlebitis or thrombophlebitis of the leg.
Clinical signs
Typical findings include localized leg pain, tenderness, swelling, warmth, and redness along a superficial or deep vein. Clinical features vary; refer to documentation and confirm the lower-extremity location and whether thrombosis is described.
When to use this code
Use I80.3 when the provider documents phlebitis, thrombophlebitis, or venous inflammation in a lower limb but does not specify the vein, laterality, or acuity. It is also appropriate when the note is too nonspecific to assign a more detailed code. If the record identifies a more specific lower-extremity vein or a different condition, code that instead.
Do not use for
Do not use this code for upper-extremity thrombophlebitis, pregnancy-related venous disorders, or venous embolism without phlebitis documentation. Check documentation if the provider specifies a different vein, site, or diagnosis.
Coding tip
Query for laterality, vein location, and acute versus chronic status before defaulting to the unspecified code.