ICD-10 Code I82.4Z9 – Acute embolism and thrombosis of unspecified deep veins of unspecified distal lower extremity (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I82.4Z9 – Acute embolism and thrombosis of unspecified deep veins of unspecified distal lower extremity
What it is
This code identifies an acute blood clot or embolus in a deep vein of the distal lower extremity when the exact side and vein are not specified. Use it for a new, current event affecting the lower leg or ankle region.
Clinical signs
Typical findings include unilateral leg pain, swelling, warmth, tenderness, or erythema. Clinical features vary; refer to documentation, and confirm that the record supports an acute deep venous event.
When to use this code
Use I82.4Z9 when the provider documents acute embolism or thrombosis in an unspecified deep vein of the distal lower extremity and does not name a more specific vein or laterality. It fits emergency, inpatient, or outpatient documentation when the clot is newly diagnosed. If the record later specifies the vein or side, code the more specific option instead.
Do not use for
Do not use this code for chronic, old, or history-only thrombosis. Check documentation if the clot is in a different location, such as proximal leg veins, superficial veins, or if the provider names a more specific ICD-10 option.
Coding tip
Code the highest available specificity first, and verify whether the documentation identifies laterality, vein, or chronicity before defaulting to this unspecified code.