You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Four days after undergoing subtotal gastrectomy for stomach cancer, a 58-year-old woman complains of right leg and thigh pain, swelling and redness, and has tenderness on examination. The diagnosis of deep vein thrombosis is entertained. What is the initial test to establish the diagnosis? and explain in detail?
The most accurate method of confirming the diagnosis of venous thrombosis is the injection of contrast material to visualize the venous system (venography). However, this method is invasive and time-consuming and must be done in the radiology suite. Venous duplex ultrasound is noninvasive, can be done bedside, and has a sensitivity and specificity of 96 and 100%, respectively. The other methods listed are used less often in certain selected patients.