title: Prospective diagnostic accuracy assessment of the HemosIL HS D-dimer to exclude pulmonary embolism in emergency department patients.
abstract: BACKGROUND
  Chest pain and shortness of breath are among the most common symptoms requiring immediate evaluation. Testing for pulmonary embolism (PE) has become easier and widespread due to D-dimer blood tests. Safe use of these tests is only possible if sensitivity is high and they are used in non-high probability patients. We evaluated diagnostic performance of the HemosIL HS D-dimer, which despite FDA approval in 2005, has been minimally reported in prospective standard clinical care.
  
  
  METHODS
  We used a prospective observational study design to follow patients in a single center with the HemosIL HS ordered for symptoms of possible PE with positive test result if >243 ng/ml. The outcome was PE or deep venous thrombosis (DVT) at the time of presentation or subsequent 45 days determined by structured evaluation of imaging tests, phone, or medical record follow-up in all patients.
  
  
  RESULTS
  529 patients received a D-dimer and 4.7% were ultimately diagnosed with PE or DVT. The sensitivity of the HemosIL HS was 96.0% (95% CI; 79.6 to 99.9%) specificity was 65.7% (95% CI; 61.4 to 69.8%) and likelihood ratio negative was 0.06 (95% CI; 0.01 to 0.42). The probability of PE in patients with a negative D-dimer was 1/332 or 0.3% (95% CI; 0.01% to 1.67%). The receiver operator curve had an area under the curve of 0.87 and supported the current cut-point as optimal.
  
  
  CONCLUSIONS
  The HemosIL HS D-dimer had high sensitivity, very low negative post-test probability and is useful in excluding PE in the acute care setting.
authors.affiliation: Northwestern University, Chicago, IL 60611, United States. mcourtney@nmff.org
authors.forename: D Mark
authors.initials: DM
authors.lastname: Courtney
authors.forename: Justin M
authors.initials: JM
authors.lastname: Steinberg
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: McCormick
mesh_terms: D000933:Antifibrinolytic Agents; D019540:Area Under Curve; D003937:Diagnosis, Differential; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005338:Fibrin Fibrinogen Degradation Products; D005500:Follow-Up Studies; D006801:Humans; D016013:Likelihood Functions; D011237:Predictive Value of Tests; D011336:Probability; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D013997:Time Factors; D020246:Venous Thrombosis / Q000175:diagnosis
chemical_list: D000933:Antifibrinolytic Agents; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D