ICD-10 Code I82.509 – Chronic embolism and thrombosis of unspecified deep veins of unspecified lower extremity (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I82.509 – Chronic embolism and thrombosis of unspecified deep veins of unspecified lower extremity
What it is
This code identifies a chronic, long-standing blood clot or embolus in a deep vein of the lower leg or thigh when the exact side is not documented. Use it when the record confirms deep vein involvement but remains nonspecific.
Clinical signs
Clinical features vary; refer to documentation. Commonly, you may see a history of prior deep vein thrombosis, persistent leg swelling, pain, skin discoloration, or venous changes, but the chart must support chronic disease.
When to use this code
Use I82.509 when the provider documents chronic embolism or thrombosis in an unspecified deep vein of an unspecified lower extremity and no laterality is stated. It is appropriate for follow-up visits, residual clot findings, or chronic venous obstruction noted on imaging or assessment. If documentation names a specific leg or vein, code more specifically.
Do not use for
Do not use this code for acute deep vein thrombosis, superficial thrombophlebitis, or embolism in a site other than the lower-extremity deep veins. Check documentation if the record does not clearly state chronicity.
Coding tip
Look for both chronic status and unspecified laterality; if either is documented more precisely, select the more specific ICD-10-CM code.