title: Clinical decision rules for excluding pulmonary embolism: a meta-analysis.
abstract: BACKGROUND
  Clinical probability assessment is combined with d-dimer testing to exclude pulmonary embolism (PE).
  
  
  OBJECTIVE
  To compare the test characteristics of gestalt (a physician's unstructured estimate) and clinical decision rules for evaluating adults with suspected PE and assess the failure rate of gestalt and rules when used in combination with d-dimer testing.
  
  
  METHODS
  Articles in MEDLINE and EMBASE in English, French, German, Italian, Spanish, or Dutch that were published between 1966 and June 2011.
  
  
  METHODS
  3 reviewers, working in pairs, selected prospective studies in consecutive patients suspected of having PE. Studies had to estimate the probability of PE by using gestalt or a decision rule and verify the diagnosis by using an appropriate reference standard.
  
  
  METHODS
  Data on study characteristics, test performance, and prevalence were extracted. Reviewers constructed 2 × 2 tables and assessed the methodological quality of the studies.
  
  
  RESULTS
  52 studies, comprising 55 268 patients, were selected. Meta-analysis was performed on studies that used gestalt (15 studies; sensitivity, 0.85; specificity, 0.51), the Wells rule with a cutoff value less than 2 (19 studies; sensitivity, 0.84; specificity, 0.58) or 4 or less (11 studies; sensitivity, 0.60; specificity, 0.80), the Geneva rule (5 studies; sensitivity, 0.84; specificity, 0.50), and the revised Geneva rule (4 studies; sensitivity, 0.91; specificity, 0.37). An increased prevalence of PE was associated with higher sensitivity and lower specificity. Combining a decision rule or gestalt with d-dimer testing seemed safe for all strategies, except when the less-sensitive Wells rule (cutoff value ≤4) was combined with less-sensitive qualitative d-dimer testing.
  
  
  CONCLUSIONS
  Studies had substantial heterogeneity due to prevalence of PE and differences in threshold. Many studies (63%) had potential bias due to differential disease verification.
  
  
  CONCLUSIONS
  Clinical decision rules and gestalt can safely exclude PE when combined with sensitive d-dimer testing. The authors recommend standardized rules because gestalt has lower specificity, but the choice of a particular rule and d-dimer test depend on both prevalence and setting.
authors.affiliation: Academic Medical Center, Amsterdam, University Medical Center Utrecht, The Netherlands. w.a.lucassen@amc.uva.nl
authors.forename: Wim
authors.initials: W
authors.lastname: Lucassen
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Geersing
authors.forename: Petra M G
authors.initials: PM
authors.lastname: Erkens
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Reitsma
authors.forename: Karel G M
authors.initials: KG
authors.lastname: Moons
authors.forename: Harry
authors.initials: H
authors.lastname: Büller
authors.forename: Henk C
authors.initials: HC
authors.lastname: van Weert
mesh_terms: D003661:Decision Support Techniques; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D005863:Gestalt Theory; D006801:Humans; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012017:Referral and Consultation; D012680:Sensitivity and Specificity; D014218:Triage; D020246:Venous Thrombosis / Q000175:diagnosis
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D