ICD-10 Code I80.203 – Phlebitis and thrombophlebitis of unspecified deep vessels of lower extremities, bilateral (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I80.203 – Phlebitis and thrombophlebitis of unspecified deep vessels of lower extremities, bilateral
What it is
This code identifies inflammation and clotting in the deep veins of both lower legs, when the specific deep vessel is not documented. Use it when the record supports bilateral deep vein involvement but does not name the exact vein.
Clinical signs
Clinical features vary; refer to documentation. Commonly noted findings include leg pain, swelling, tenderness, warmth, or redness, with bilateral deep venous disease supported by imaging or provider assessment.
When to use this code
Use I80.203 when the provider documents phlebitis or thrombophlebitis in unspecified deep vessels of both lower extremities. It also fits when the note confirms bilateral deep vein thrombosis or thrombophlebitis but does not identify a more specific vessel.
If the documentation later specifies a particular deep vein, code the more specific option instead. Check documentation when laterality, acuity, or vessel detail is unclear.
Do not use for
Do not use this code for superficial thrombophlebitis, upper-extremity disease, or unilateral lower-extremity involvement. Do not assign it when the chart identifies a more specific deep vein code.
Coding tip
Confirm both bilateral involvement and deep-vessel location in the provider record before assigning I80.203.