Deep vein thrombosis (DVT) is an important, treatable disease that can be diagnosed by noninvasive imaging procedures. Ultrasound is the most accurate and readily available of these modalities but it still has limitations. False positive results occur in up 6% of patients, and calf DVT is not readily detected; thus serial ultrasonography is recommended in order to detect extension of a calf DVT. However, this results in many patients needlessly returning for a repeat assessment. A recently developed clinical model has the potential to identify false positive ultrasound results and to select patients who do not require serial testing. Certain rapidly performed D-dimer assays have similar potential but have not been evaluated in management strategies. In the subgroup of patients with suspected recurrent DVT and asymptomatic patients at high risk for DVT, ultrasonography and impedance plethysmography are less accurate, however, the clinical implications of this are unknown.