The main objective of the trial is to determine whether D-dimer testing combined with assessment of Pre-Test-Probability (using a standardized clinical model) can be used to markedly simplify the diagnostic process for PE.

It may be safe to omit additional diagnostic testing in selected patients with suspected pulmonary embolism who have a negative D-dimer test

To assess the value of the D-dimer in the diagnosis of PE, we had two sub-groups of patients with suspected PE, low and high pre-test probability. Patients could be randomized either to further or no further testing.

Inclusion Criteria:

• Patients with clinically suspected PE

Exclusion Criteria:

• Treatment with anticoagulants for greater than 24 hours of performance of D-d
• Comorbid condition limiting survival to less than 3 months
• Absence of acute symptoms within 7 days prior to presentation
• Current pregnancy
• Contraindication to contrast (e.g., allergy, renal failure)
• Geographic inaccessibility which precludes follow-up
• Physician believes patient is inappropriate for study
• failure or inability to provide informed consent