title: The use of D-dimer testing and impedance plethysmographic examination in patients with clinical indications of deep vein thrombosis.
abstract: OBJECTIVE
  To prospectively test the hypothesis that a diagnosis of deep vein thrombosis can be excluded in outpatients who present with clinical indications of deep vein thrombosis and whose results of D-dimer testing and impedance plethysmographic examination on the day of presentation are normal.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Four university-affiliated hospitals.
  
  
  METHODS
  Three hundred ninety-eight consecutive patients with clinical indications of deep vein thrombosis were included in the final analysis. All patients underwent an assessment of pretest probability, bedside D-dimer testing, and impedance plethysmographic examination. In most patients, if the results of D-dimer testing and impedance plethysmographic examination were negative for deep vein thrombosis, anticoagulants were withheld and patients were followed up for 3 months. If the results of one or both tests were abnormal, an examination using venous compression ultrasonography or phlebography was performed.
  
  
  RESULTS
  In the majority of patients (69%), the results of D-dimer testing and impedance plethysmographic examination were normal. This combination had a negative predictive value of 98.5% (95% confidence interval, 96.3-99.6) for deep vein thrombosis.
  
  
  CONCLUSIONS
  The results of the D-dimer assay and impedance plethysmographic examination on the day of presentation can be used to treat the majority of outpatients who present with clinical indications of deep vein thrombosis without further testing.
authors.affiliation: Department of Medicine, McMaster University, Hamilton, Ontario.
authors.forename: J S
authors.initials: JS
authors.lastname: Ginsberg
authors.forename: C
authors.initials: C
authors.lastname: Kearon
authors.forename: J
authors.initials: J
authors.lastname: Douketis
authors.forename: A G
authors.initials: AG
authors.lastname: Turpie
authors.forename: P
authors.initials: P
authors.lastname: Brill-Edwards
authors.forename: P
authors.initials: P
authors.lastname: Stevens
authors.forename: A
authors.initials: A
authors.lastname: Panju
authors.forename: A
authors.initials: A
authors.lastname: Patel
authors.forename: M
authors.initials: M
authors.lastname: Crowther
authors.forename: M
authors.initials: M
authors.lastname: Andrew
authors.forename: P
authors.initials: P
authors.lastname: Massicotte
authors.forename: J
authors.initials: J
authors.lastname: Hirsh
authors.forename: J I
authors.initials: JI
authors.lastname: Weitz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care; D000925:Anticoagulants / Q000627:therapeutic use; D000933:Antifibrinolytic Agents / Q000097:blood*; D015331:Cohort Studies; D016001:Confidence Intervals; D003937:Diagnosis, Differential; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010690:Phlebography; D010992:Plethysmography, Impedance; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D013924:Thrombophlebitis / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014463:Ultrasonography
chemical_list: D000925:Anticoagulants; D000933:Antifibrinolytic Agents; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D