Bilateral lower extremity US in the patient with unilateral symptoms of deep venous thrombosis: assessment of need.

PURPOSE: To assess the need for bilateral ultrasound (US) evaluation for lower extremity deep venous thrombosis (DVT) regardless of predisposing factors in patients with unilateral symptoms. MATERIALS AND METHODS: Two hundred six patients with unilateral lower extremity symptoms suggestive of DVT were evaluated prospectively for predisposing factors and symptoms. Bilateral examinations were performed in all patients, and the prevalences of US-diagnosed DVT in symptomatic and in asymptomatic extremities were determined. RESULTS: Thirty-seven of the 206 patients had DVT in the symptomatic extremity. Twenty-five of these 37 patients had predisposing factors. No DVT was found in any asymptomatic extremity. Because compression US has a sensitivity and a specificity of greater than 90% for the diagnosis of DVT, these results were statistically significant (P < .001). CONCLUSION: Regardless of predisposing factors, US screening for DVT in the lower extremities should be limited to the symptomatic extremity in patients with unilateral symptoms. This would decrease scanning time and cost without a decline in the DVT detection rate.