Safety of a Diagnostic Strategy With D-Dimer Testing for PE

Inclusion Criteria: * Age 18 years or older * Suspected PE Exclusion Criteria: * Treatment with full-dose anticoagulants for 24 hours or more OR an ongoing requirement for anticoagulants * Other tests for PE performed prior to eligibility assessment (e.g.other D-Dimer, V/Q scan, pulmonary angiogram, spiral CT, compression ultrasound, venogram). * Cardiorespiratory instability requiring immediate performance of other tests to diagnose or exclude PE (i.e. inability to wait 30-60 minutes for MDA D-Dimer result) * Comorbid condition limiting survival to less than three months * Patient has been asymptomatic for seven days prior to presentation * Current pregnancy * Contraindication to contrast (e.g., allergy, renal failure). * Geographic in accessibility which precludes follow-up * Presence of central venous catheter (permanent or temporary, including PICC line) at the time of eligibility assessment