title: Is the ordering of imaging for suspected venous thromboembolism consistent with D-dimer result?
abstract: OBJECTIVE
  We assessed whether the ordering of imaging studies in patients with suspected venous thromboembolism was consistent with the results of D-dimer testing.
  
  
  METHODS
  We performed a retrospective chart review of consecutive cases in which a D-dimer assay was performed at an urban academic emergency department during a 13-month period. Measurements included D-dimer result and results of imaging for venous thromboembolism. The primary outcome measure was the percentage of patients in each D-dimer category (positive or negative result with a cutoff value of 500 ng fibrinogen equivalent units/dL) who underwent subsequent imaging within 48 hours. We also report the results of the imaging studies obtained.
  
  
  RESULTS
  A total of 553 D-dimer tests were ordered, with 266 (48.1%) negative and 287 (51.9%) positive results. Of patients with a negative D-dimer result, 37 (14%; 95% confidence interval [CI] 10% to 19%) underwent at least 1 imaging study. Of patients with a positive D-dimer result, 137 (48%; 95% CI 42% to 54%) did not undergo imaging.
  
  
  CONCLUSIONS
  Evaluation for venous thromboembolism occasionally proceeded despite a negative D-dimer result, whereas frequently no further evaluation occurred despite a positive result. These findings suggest that actual clinical practice differs from what is recommended by published algorithms that guide evaluation of patients with suspected venous thromboembolism.
authors.affiliation: Department of Emergency Medicine, Alameda County Medical Center-Highland Hospital, Oakland, CA 94602, USA. nateismann@gmail.com
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Teismann
authors.forename: Paul T
authors.initials: PT
authors.lastname: Cheung
authors.forename: Bradley
authors.initials: B
authors.lastname: Frazee
mesh_terms: D000046:Academic Medical Centers; D004635:Emergency Medicine / Q000379:methods; D004636:Emergency Service, Hospital; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D019983:Guideline Adherence; D006786:Hospitals, Urban; D006801:Humans; D010690:Phlebography; D010818:Practice Patterns, Physicians'; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis*; D012189:Retrospective Studies; D054556:Venous Thromboembolism / Q000097:blood / Q000175:diagnosis*; D014692:Ventilation-Perfusion Ratio
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D