title: Assessment of the pulmonary embolism rule-out criteria rule for evaluation of suspected pulmonary embolism in the emergency department.
abstract: BACKGROUND
  Overuse of resources when evaluating pulmonary embolism (PE) is a concern if the D-dimer assay is improperly used in the evaluation of emergency department patients with suspected PE. The pulmonary embolism rule-out criteria (PERC) rule was derived to prevent unnecessary diagnostic testing in this patient population. The objective of this study was to assess the PERC rule's performance in an external population.
  
  
  METHODS
  This was a secondary analysis of a prospectively collected database comparing PERC rule variables to diagnosis of PE in consecutive patients with suspicion for PE. Bivariate analysis on individual variables and the overall accuracy of the PERC rule were performed.
  
  
  RESULTS
  Patients on 120 randomly assigned shifts were enrolled with a PE prevalence of 12%. The sensitivity, specificity, positive predictive, and negative predictive values of the PERC rule were 100% (95% confidence interval [CI], 79%-100%), 16% (95% CI, 10%-24%), 14% (95% CI, 8%-14%), and 100% (95% CI, 80%-100%), respectively, for the total patient population, and 100% (95% CI, 25%-100%), 33% (95% CI, 12%-35%), 2% (95% CI, 0%-11%), and 100% (95% CI, 75%-100%), respectively, for the low pretest probability population. Bivariate analysis showed unilateral leg swelling, recent surgery, and a history of venous thromboembolic event to be predictive of the diagnosis of PE.
  
  
  CONCLUSIONS
  The PERC rule may identify a cohort of patients with suspected PE for whom diagnostic testing beyond history and physical examination is not indicated.
authors.affiliation: Department of Emergency Medicine, Denver Health Medical Center, Denver, CO 80204, USA. stephen.wolf@dhha.org
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Wolf
authors.forename: Tracy R
authors.initials: TR
authors.lastname: McCubbin
authors.forename: Kristen E
authors.initials: KE
authors.lastname: Nordenholz
authors.forename: N Ward
authors.initials: NW
authors.lastname: Naviaux
authors.forename: Jason S
authors.initials: JS
authors.lastname: Haukoos
mesh_terms: D000328:Adult; D000368:Aged; D019992:Databases as Topic; D004636:Emergency Service, Hospital; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis*; D012680:Sensitivity and Specificity
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D