title: A negative SimpliRED D-dimer assay result does not exclude the diagnosis of deep vein thrombosis or pulmonary embolus in emergency department patients.
abstract: OBJECTIVE
  To determine whether a negative SimpliRED D-dimer assay result excludes the diagnosis of deep vein thrombosis (DVT) or pulmonary embolus (PE) in emergency department patients.
  
  
  METHODS
  This prospective, institutional review board-approved, clinical trial enrolled consecutive adult ED patients with the suspected diagnosis of venous thromboembolism (VTE) (DVT or PE). Initial ED evaluation included the SimpliRED D-dimer assay (American Diagnostica Inc, Greenwich, CT). Physicians were blinded to assay results. The diagnosis of DVT was made with positive findings on lower-extremity ultrasonography. PE was confirmed by a high-probability ventilation/perfusion (V/Q) scan, a positive pulmonary angiogram, or a positive finding on lower-extremity ultrasonography. A presumptive diagnosis of VTE was made in patients who had VTE at follow-up or unexplained death during the study period.
  
  
  RESULTS
  One hundred ninety-eight patients were enrolled during the study period. Twenty-five patients were excluded from data analysis; 9 had no diagnostic testing and 16 were lost to follow-up. Of the 173 patients analyzed, 57 (33%) had VTE-16 of 48 evaluated for DVT and 41 of 125 for suspected PE. The SimpliRED assay had a sensitivity of 65% and a negative predictive value of 81% for detection of VTE. In patients evaluated for DVT alone, the sensitivity was 56% and the negative predictive value was 77%. For patients with suspected PE, the sensitivity and negative predictive value were 68% and 83%, respectively.
  
  
  CONCLUSIONS
  In contrast to earlier reports on the SimpliRED D-dimer assay, a negative result failed to exclude the diagnosis of VTE in our ED population.
authors.affiliation: Departments of Emergency Medicine and Clinical Pathology, Maine Medical Center, Portland, ME 04102, USA. nfarrell@maine.rr.com
authors.forename: S
authors.initials: S
authors.lastname: Farrell
authors.forename: T
authors.initials: T
authors.lastname: Hayes
authors.forename: M
authors.initials: M
authors.lastname: Shaw
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006386:Hemagglutination Tests; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D014692:Ventilation-Perfusion Ratio
chemical_list: D005338:Fibrin Fibrinogen Degradation Products