ICD-10 Code I82.91 – Chronic embolism and thrombosis of unspecified vein (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I82.91 – Chronic embolism and thrombosis of unspecified vein
What it is
This code identifies a long-standing blood clot or embolic blockage in a vein that is not further specified. Use it when the record confirms chronic venous thrombosis but does not name the exact vein.
Clinical signs
Clinical features vary; refer to documentation. Chronic venous obstruction may be described with persistent swelling, discomfort, skin changes, or a history of prior thrombosis, but the record must support chronicity.
When to use this code
Use I82.91 when the provider documents chronic embolism and thrombosis and does not identify a specific vein. It also fits when imaging or follow-up notes describe an old, persistent venous clot without more detail. If the site is named, choose the more specific code.
Do not use for
Do not use this code for acute or newly diagnosed thrombosis. Do not use it when the documentation identifies a specific vein or another vascular condition instead.
Coding tip
Check the note for chronicity and vein location before assigning I82.91.