title: Prospective multicenter evaluation of the pulmonary embolism rule-out criteria.
abstract: BACKGROUND
  Over-investigation of low-risk patients with suspected pulmonary embolism (PE) represents a growing problem. The combination of gestalt estimate of low suspicion for PE, together with the PE rule-out criteria [PERC(-): age < 50 years, pulse < 100 beats min(-1), SaO(2) >or= 95%, no hemoptysis, no estrogen use, no surgery/trauma requiring hospitalization within 4 weeks, no prior venous thromboembolism (VTE), and no unilateral leg swelling], may reduce speculative testing for PE. We hypothesized that low suspicion and PERC(-) would predict a post-test probability of VTE(+) or death below 2.0%.
  
  
  METHODS
  We enrolled outpatients with suspected PE in 13 emergency departments. Clinicians completed a 72-field, web-based data form at the time of test order. Low suspicion required a gestalt pretest probability estimate of <15%. The main outcome was the composite of image-proven VTE(+) or death from any cause within 45 days.
  
  
  RESULTS
  We enrolled 8138 patients, 85% of whom had a chief complaint of either dyspnea or chest pain. Clinicians reported a low suspicion for PE, together with PERC(-), in 1666 patients (20%). At initial testing and within 45 days, 561 patients (6.9%, 95% confidence interval 6.5-7.6) were VTE(+), and 56 others died. Among the low suspicion and PERC(-) patients, 15 were VTE(+) and one other patient died, yielding a false-negative rate of 16/1666 (1.0%, 0.6-1.6%). As a diagnostic test, low suspicion and PERC(-) had a sensitivity of 97.4% (95.8-98.5%) and a specificity of 21.9% (21.0-22.9%).
  
  
  CONCLUSIONS
  The combination of gestalt estimate of low suspicion for PE and PERC(-) reduces the probability of VTE to below 2% in about 20% of outpatients with suspected PE.
authors.affiliation: Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC 28323-2861, USA. jkline@carolinas.org
authors.forename: J A
authors.initials: JA
authors.lastname: Kline
authors.forename: D M
authors.initials: DM
authors.lastname: Courtney
authors.forename: C
authors.initials: C
authors.lastname: Kabrhel
authors.forename: C L
authors.initials: CL
authors.lastname: Moore
authors.forename: H A
authors.initials: HA
authors.lastname: Smithline
authors.forename: M C
authors.initials: MC
authors.lastname: Plewa
authors.forename: P B
authors.initials: PB
authors.lastname: Richman
authors.forename: B J
authors.initials: BJ
authors.lastname: O'Neil
authors.forename: K
authors.initials: K
authors.lastname: Nordenholz
mesh_terms: D000465:Algorithms; D003936:Diagnosis, Computer-Assisted / Q000379:methods* / Q000592:standards; D003937:Diagnosis, Differential; D005188:False Negative Reactions; D006801:Humans; D011336:Probability; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D054556:Venous Thromboembolism