DVT and pulmonary embolism: Choosing the right diagnostic tests for patients at risk

Accurate diagnosis of deep-vein thrombosis (DVT) and pulmonary embolism (PE) is essential to deciding whether to initiate anticoagulant therapy. Diagnostic testing is required in four groups of patients: those with a suspected first DVT those at high risk for DVT but who are asymptomatic, those with suspected recurrent DVT, and those with suspected PE. Serial ultrasonography (US), serial impedance plethysmography (IPG), or venography are indicated for patients with a suspected first or recurrent DVT. Asymptomatic patients at high risk for DVT require US testing, although no noninvasive test is accurate. Ventilation-perfusion lung scanning is the initial test of choice when PE is suspected, but it is nondiagnostic in up to 60% of patients. Subsequent testing depends on the patient's probability for PE.