title: Can the tandem measurement of age adjusted D-dimer and tissue plasminagen activator improve the clinical utility of a conventional D-dimer in the pulmonary embolism diagnosis?
abstract: BACKGROUND
  The aim of this study was to evaluate if a sequential measurement of age adjust D-dimer (ADD) and tissue plasminogen activator (tPA) could increase the clinical utility in patients with suspected pulmonary embolism (PE) compared to a conventional D-dimer.
  
  
  METHODS
  We measured a conventional D-dimer (CDD), an ADD alone and a sequential combination ADD and tPA (ADD/tPA combination) in a prospective sample of 127 outpatients with PE suspected. Diagnosis of PE was based on a strict protocol. Plasma sample to measure levels of tPA and D-dimer was obtained at enrollment, and CDD, ADD and tPA were assessed at the end of study. For CDD the cut-off value was 500 ng/mL and for ADD the cut-off value was defined as (patient's age x10) ng/mL in patients aged >50. We compared the sensitivity, specificity and clinical utility obtained for CDD, ADD alone, and ADD/tPA combination.
  
  
  RESULTS
  PE was confirmed in 41 patients (32%). The sensitivity, specificity and clinical utility for CDD were 95%, 36% and 28%, respectively. The ADD/tPA combination and ADD alone demonstrated an increased in specificity of +29% and +12% respectively, and increased in clinical utility of +20% and +8%, respectively, compared to CDD, and this was obtained without loss of sensitivity.
  
  
  CONCLUSIONS
  The ADD/tPA combination substantially increased the clinical utility in the PE diagnosis compared with conventional D-dimer, without reducing the security. The ADD/tPA combination could decrease the need for pulmonary vascular imaging for the PE diagnosis in nearly the half. These promising results should be validated prospectively.
authors.affiliation: Section of Pneumology, Príncipe de Asturias University Hospital, Alcalá de Henares, Madrid, Spain - jflores.hupa@salud.madrid.org.
authors.forename: Julio
authors.initials: J
authors.lastname: Flores
authors.forename: Angel
authors.initials: A
authors.lastname: García-Avello
authors.forename: Antonio
authors.initials: A
authors.lastname: Ruíz
authors.forename: Esther
authors.initials: E
authors.lastname: Alonso
authors.forename: Concepción
authors.initials: C
authors.lastname: Álvarez
authors.forename: Olga
authors.initials: O
authors.lastname: Navarrete
authors.forename: Ignacio
authors.initials: I
authors.lastname: Arribas
mesh_terms: D000367:Age Factors; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006403:Hematologic Tests / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000097:blood* / Q000175:diagnosis*; D012189:Retrospective Studies; D010959:Tissue Plasminogen Activator / Q000097:blood*
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; D010959:Tissue Plasminogen Activator