To determine whether d-dimer testing can be used to simplify and reduce the costs of the diagnostic approach to patients with clinically suspected deep vein thrombosis

Inclusion Criteria:

• first suspected deep vein thrombosis
• no previous venous thromboembolism
• referred to thromboembolism outpatient clinic

Exclusion Criteria:

• comorbid condition limiting survival to less than six months
• contraindication to venography (contrast allergy, etc.)
• receiving long term warfarin therapy
• receiving full dose heparin therapy for more than 48 hours
• absence of symptoms during the five days immediately prior to presentation
• symptoms of pulmonary embolism
• pregnancy
• geographic inaccessibility which precludes follow-up