title: A comparison of spiral computed tomography and latex agglutination D-dimer assay in acute pulmonary embolism using pulmonary arteriography as gold standard.
abstract: OBJECTIVE
  To compare the diagnostic accuracy of contrast medium enhanced spiral computed tomography of the pulmonary arteries (s-CTPA) and a latex agglutination D-dimer assay in patients with suspected acute pulmonary embolism (PE) by using pulmonary arteriography (PA) and clinical follow-up as reference method.
  
  
  METHODS
  Ninety hemodynamically stable patients with symptoms of acute pulmonary embolism were prospectively evaluated with s-CTPA and pulmonary arteriography (PA) within 24 h from admission. Plasma D-dimer levels on admittance were analyzed using a rapid latex agglutination D-dimer assay. The outcome of D-dimer concentrations in plasma below 0.25 and 0.5 mg/l was studied.
  
  
  RESULTS
  All PA and s-CTPA investigations were regarded as of acceptable diagnostic quality in a consensus reading. Thirty-three patients had a positive PA (37%). Three patients had false negative and two patients had false positive s-CTPA findings. s-CTPA had 91% sensitivity, 96% specificity, 94% positive predictive value (PPV) and 95% negative predictive value (NPV). The sensitivity and specificity for D-dimer below 0.5 mg/l were 79 and 88%, respectively. The PPV and NPV were 81 and 87%. If a cut-off level of 0.25 mg/l was used the corresponding figures were 91, 65, 63 and 92%.
  
  
  CONCLUSIONS
  s-CTPA has a higher sensitivity and specificity than latex agglutination D-dimer. A cut-off level of 0.25 mg/l can be used as screening method, but s-CTPA must be performed to exclude false positive cases.
authors.affiliation: Department of Thoracic Radiology, Karolinska Hospital, SE-171 76 Stockholm, Sweden. tage.nilsson@ks.se
authors.forename: Tage
authors.initials: T
authors.lastname: Nilsson
authors.forename: Mårten
authors.initials: M
authors.lastname: Söderberg
authors.forename: Gunilla
authors.initials: G
authors.lastname: Lundqvist
authors.forename: Kerstin
authors.initials: K
authors.lastname: Cederlund
authors.forename: Flemming
authors.initials: F
authors.lastname: Larsen
authors.forename: Elsbeth
authors.initials: E
authors.lastname: Rasmussen
authors.forename: Bertil
authors.initials: B
authors.lastname: Svane
authors.forename: Johan
authors.initials: J
authors.lastname: Brohult
authors.forename: Hans
authors.initials: H
authors.lastname: Johnsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D005189:False Positive Reactions; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D007841:Latex Fixation Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D015415:Biomarkers; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D