title: Management of suspected deep venous thrombosis in outpatients by using clinical assessment and D-dimer testing.
abstract: BACKGROUND
  When deep venous thrombosis is suspected, objective testing is required to confirm or refute the diagnosis.
  
  
  OBJECTIVE
  To determine whether the combination of a low clinical suspicion and a normal D -dimer result rules out deep venous thrombosis.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Three tertiary care hospitals in Canada.
  
  
  METHODS
  445 outpatients with a suspected first episode of deep venous thrombosis.
  
  
  METHODS
  Patients were categorized as having low, moderate, or high pretest probability of thrombosis and underwent whole-blood D -dimer testing. Patients with a low pretest probability and a negative result on the D -dimer test had no further diagnostic testing and received no anticoagulant therapy. Additional diagnostic testing was done in all other patients.
  
  
  METHODS
  Venous thromboembolic events during 3-month follow-up.
  
  
  RESULTS
  177 (40%) patients had both a low pretest probability and a negative D -dimer result. One of these patients had deep venous thrombosis during follow-up (negative predictive value, 99.4% [95% CI, 96.9% to 100%]).
  
  
  CONCLUSIONS
  The combination of a low pretest probability of deep venous thrombosis and a negative result on a whole-blood D -dimer test rules out deep venous thrombosis in a large proportion of symptomatic outpatients.
authors.affiliation: McMaster University Clinic, Room 401, Henderson General Hospital, 711 Concession Street; Hamilton, Ontario L8V 1C3, Canada.
authors.forename: C
authors.initials: C
authors.lastname: Kearon
authors.forename: J S
authors.initials: JS
authors.lastname: Ginsberg
authors.forename: J
authors.initials: J
authors.lastname: Douketis
authors.forename: M
authors.initials: M
authors.lastname: Crowther
authors.forename: P
authors.initials: P
authors.lastname: Brill-Edwards
authors.forename: J I
authors.initials: JI
authors.lastname: Weitz
authors.forename: J
authors.initials: J
authors.lastname: Hirsh
mesh_terms: D000553:Ambulatory Care; D002170:Canada; D004797:Enzyme-Linked Immunosorbent Assay; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D005500:Follow-Up Studies; D006801:Humans; D011446:Prospective Studies; D018570:Risk Assessment; D020246:Venous Thrombosis / Q000175:diagnosis*
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D