title: Review of the evidence on diagnosis of deep venous thrombosis and pulmonary embolism.
abstract: OBJECTIVE
  This review summarizes the evidence regarding the efficacy of techniques for diagnosis of deep venous thrombosis (DVT) and pulmonary embolism.
  
  
  METHODS
  We searched for studies using MEDLINE, MICROMEDEX, the Cochrane Controlled Trials Register, and the Cochrane Database of Systematic Reviews through June 2006. We reviewed randomized controlled trials, systematic reviews of trials, and observational studies if no trials were available. Paired reviewers assessed the quality of each included article and abstracted the data into summary tables. Heterogeneity in study designs precluded mathematical combination of the results of the primary literature.
  
  
  RESULTS
  Our review found 22 relevant systematic reviews and 36 primary studies. The evidence strongly supports the use of clinical prediction rules, particularly the Wells model, for establishing the pretest probability of DVT or pulmonary embolism in a patient before ordering more definitive testing. Fifteen studies support that when a D-dimer assay is negative and a clinical prediction rule suggests a low probability of DVT or pulmonary embolism, the negative predictive value is high enough to justify foregoing imaging studies in many patients. The evidence in 5 systematic reviews regarding the use of D-dimer, in isolation, is strong and demonstrates sensitivities of the enzyme-linked immunosorbent assay (ELISA) and quantitative rapid ELISA, pooled across studies, of approximately 95%. Eight systematic reviews found that the sensitivity and specificity of ultrasonography for diagnosis of DVT vary by vein; ultrasonography performs best for diagnosis of symptomatic, proximal vein thrombosis, with pooled sensitivities of 89% to 96%. The sensitivity of single-detector helical computed tomography for diagnosis of pulmonary embolism varied widely across studies and was below 90% in 4 of 9 studies; more studies are needed to determine the sensitivity of multidetector scanners.
  
  
  CONCLUSIONS
  While the strength of the evidence varies across questions, it is generally strong.
authors.affiliation: Johns Hopkins University School of Medicine, Department of Medicine, Baltimore, MD, USA. jsegal@jhmi.edu
authors.forename: Jodi B
authors.initials: JB
authors.lastname: Segal
authors.forename: John
authors.initials: J
authors.lastname: Eng
authors.forename: Leonardo J
authors.initials: LJ
authors.lastname: Tamariz
authors.forename: Eric B
authors.initials: EB
authors.lastname: Bass
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D006801:Humans; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000453:epidemiology
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D