Algorithm for diagnosing DVT using clinical assessment, venous ultrasonography, and D-dimer testing.

#Re-evaluate history and review ultrasound for features suggestive of old rather than new thrombosis. If ultrasound findings are inconclusive, venography should be considered. *In patients with a high clinical probability or who cannot return for serial ultrasonography, venography is recommended. Venography can also be considered in patients with cardiorespiratory compromise.