Diagnosing pulmonary embolism in outpatients with clinical assessment, D-dimer measurement, venous ultrasound, and helical computed tomography: a multicenter management study

Am J Med. 2004 Mar 1;116(5):291-9. doi: 10.1016/j.amjmed.2003.09.041.


Purpose: To evaluate a diagnostic strategy for pulmonary embolism that combined clinical assessment, plasma D-dimer measurement, lower limb venous ultrasonography, and helical computed tomography (CT).

Methods: A cohort of 965 consecutive patients presenting to the emergency departments of three general and teaching hospitals with clinically suspected pulmonary embolism underwent sequential noninvasive testing. Clinical probability was assessed by a prediction rule combined with implicit judgment. All patients were followed for 3 months.

Results: A normal D-dimer level (<500 microg/L by a rapid enzyme-linked immunosorbent assay) ruled out venous thromboembolism in 280 patients (29%), and finding a deep vein thrombosis by ultrasonography established the diagnosis in 92 patients (9.5%). Helical CT was required in only 593 patients (61%) and showed pulmonary embolism in 124 patients (12.8%). Pulmonary embolism was considered ruled out in the 450 patients (46.6%) with a negative ultrasound and CT scan and a low-to-intermediate clinical probability. The 8 patients with a negative ultrasound and CT scan despite a high clinical probability proceeded to pulmonary angiography (positive: 2; negative: 6). Helical CT was inconclusive in 11 patients (pulmonary embolism: 4; no pulmonary embolism: 7). The overall prevalence of pulmonary embolism was 23%. Patients classified as not having pulmonary embolism were not anticoagulated during follow-up and had a 3-month thromboembolic risk of 1.0% (95% confidence interval: 0.5% to 2.1%).

Conclusion: A noninvasive diagnostic strategy combining clinical assessment, D-dimer measurement, ultrasonography, and helical CT yielded a diagnosis in 99% of outpatients suspected of pulmonary embolism, and appeared to be safe, provided that CT was combined with ultrasonography to rule out the disease.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Emergency Service, Hospital
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fibrin Fibrinogen Degradation Products / analysis*
  • Humans
  • Leg / blood supply
  • Male
  • Middle Aged
  • Outcome Assessment, Health Care
  • Probability
  • Prospective Studies
  • Pulmonary Artery / diagnostic imaging
  • Pulmonary Embolism / complications
  • Pulmonary Embolism / diagnosis*
  • Pulmonary Embolism / diagnostic imaging
  • Sensitivity and Specificity
  • Tomography, Spiral Computed*
  • Ultrasonography
  • Venous Thrombosis / complications
  • Venous Thrombosis / diagnostic imaging*


  • Fibrin Fibrinogen Degradation Products
  • fibrin fragment D