ICD-10 Code I80.229 – Phlebitis and thrombophlebitis of unspecified popliteal vein (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I80.229 – Phlebitis and thrombophlebitis of unspecified popliteal vein
What it is
This code identifies inflammation of a popliteal vein with a clot, when the affected side is not documented. It is used for venous thrombophlebitis involving the vein behind the knee.
Clinical signs
Typical findings include leg pain, tenderness, swelling, warmth, or redness along the affected vein. Clinical features vary; refer to documentation, and confirm the popliteal vein is involved.
When to use this code
Use this code when the record states phlebitis or thrombophlebitis of the popliteal vein but does not specify right or left. It also fits when the clinician documents a popliteal vein clot with inflammation and laterality is missing. Check documentation if the note only mentions deep vein thrombosis without phlebitis.
Do not use for
Do not use this code if the documentation identifies a different vein, such as femoral, tibial, or unspecified lower-extremity vein. Also avoid it when laterality is documented and a more specific code applies.
Coding tip
Verify laterality and vein location in the assessment, imaging report, or discharge summary before assigning the unspecified code.