The emergency department utility of Simplify D-dimer™ to exclude pulmonary embolism in patients with pleuritic chest pain

Study objective: Pleuritic chest pain is a common presenting complaint in the emergency department (ED) and a symptom of pulmonary embolism. Patients with pleuritic chest pain would benefit from a simple and rapid way of screening for pulmonary embolism. The aim of this study is to assess the utility of Simplify D-dimer(TM) as a rule-out tool for pulmonary embolism in ED patients with pleuritic chest pain. Methods: This was a prospective diagnostic study in a large city-center ED. Four hundred twenty-five patients with pleuritic chest pain were prospectively recruited between February 2002 and June 2003. Simplify D-dimer(TM) testing was performed on each patient in the ED. All patients followed an independent reference standard diagnostic algorithm for pulmonary embolism. Each patient was followed up clinically for 3 months. Results: The calculated sensitivity of Simplify D-dimer(TM) for pulmonary embolism was 81.8% (95% confidence interval [CI] 61.4% to 92.7%), and specificity was 74.2% (95% CI 69.6% to 78.4%). The negative predictive value was 98.6% (95% CI 96.6% to 99.6%), positive predictive value 15.0% (95% CI 9.1% to 22.7%), negative likelihood ratio 0.25 (95% CI 0.10 to 0.52) and positive likelihood ratio 3.17 (95% CI 2.30 to 3.97). The study cohort pretest probability was 5.3%. A negative Simplify result reduced the posttest probability to 1.3% (95% CI 0.5% to 3.4%). Conclusion: The Simplify D-dimer(TM) is not sufficiently sensitive to exclude the diagnosis of pulmonary embolism in all patients presenting to the ED with pleuritic chest pain.