What is the primary diagnostic tool for deep vein thrombosis (DVT)?

The primary diagnostic tool for deep vein thrombosis (DVT) is an ultrasound or Doppler examination of the extremity. This non-invasive imaging technique is particularly effective because it can visualize the veins directly and assess for the presence of thrombus (clot) in the deep venous system. The ultrasound utilizes sound waves to create images of the blood flow in the veins, allowing healthcare providers to identify any obstructions caused by clots.

Other methods such as CT scans or physical examinations are not typically used as the first line of assessment for DVT. A CT chest with IV contrast dye is more suited for diagnosing pulmonary embolisms or other conditions of the lungs and heart rather than DVT. Similarly, a US scrotum is utilized for assessing conditions specific to the male reproductive system. Physical examination may suggest the presence of DVT through signs like swelling and tenderness, but it is not definitive and can be misleading. Thus, Doppler ultrasound is the standard for confirming DVT due to its accuracy and ease of use.