Update on the lower extremity venous ultrasonography examination.

Lower extremity venous ultrasonography is an accurate method to diagnose acute deep venous thrombosis (DVT). Recurrent DVT is often difficult diagnosis. The decision to order ultrasonography can be based on pretest risk assessment. If the ultrasonography study is negative, the report may recommend follow-up for patients whose clinical condition changes or for patients with specific risks. Lower extremity venous ultrasonography is the gold standard for diagnosis of DVT. It is accurate and objective, and because the clinical assessment of patients is limited and its potential complication, pulmonary embolism, is significant, the impact of a positive and negative test is high.