DVT is a blood clot in a vein, usually in the leg. Symptoms can include throbbing pain, swelling, skin colour change or swollen veins, often on one side. These symptoms can have other causes, so you need an urgent clinical assessment if you think you may have DVT.[1]
Call 999 or go to A&E now
Call 999 or go to A&E if you have possible DVT symptoms and chest pain or shortness of breath. Do not drive yourself. These symptoms can occur with pulmonary embolism, which needs urgent treatment.[1]
When to get urgent advice
If you think you have DVT without chest pain or breathlessness, seek an urgent GP appointment or NHS 111. Pregnancy, recent surgery, reduced mobility, a long journey, previous DVT, some medicines and some health conditions can affect risk. A risk factor does not diagnose DVT, and DVT can occur without an obvious cause.[1]
How clinicians assess possible DVT
A clinician considers your symptoms, history and examination before choosing a diagnostic pathway. NICE NG158 covers assessment and management of suspected venous thromboembolic disease in adults. A clinical probability tool may inform that pathway, but it is not for self-diagnosis or deciding treatment from this page.[2]
What ultrasound can and cannot tell you
Ultrasound can be used to assess blood flow in veins as part of an urgent diagnostic pathway. The right examination, its timing, interpretation and next step depend on the clinical assessment. A scan result does not replace urgent emergency assessment when concerning chest symptoms are present.
After assessment
If DVT is confirmed or strongly suspected, a clinician will arrange the appropriate management and follow-up. Treatment decisions, including medicines, depend on the person and clinical setting. Do not start, stop or alter anticoagulant medicine based on this guide.