title: Clinical usefulness of adjusted D-dimer cut-off values to exclude pulmonary embolism in a community hospital emergency department patient population.
abstract: BACKGROUND
  Plasma D-dimer measurement is used in the assessment of the clinical probability of pulmonary embolism (PE), in order to minimize the requirement for pulmonary computed tomography angiography (CTA).
  
  
  OBJECTIVE
  To evaluate whether doubling the threshold value of serum D-dimer from 500 μg/L to 1000 μg/L could safely reduce utilization of pulmonary CTA to exclude PE in our emergency department patient population.
  
  
  METHODS
  Emergency department patients evaluated for PE with a quantitative D-dimer assay and pulmonary CTA were eligible for inclusion. D-dimer values were retrospectively collected in all included patients. Pulmonary CT angiograms were reviewed and scored as positive or negative for PE. Receiver-operating characteristic (ROC) analysis was used to determine the accuracy of quantitative D-dimer measurements in differentiating between positive and negative PE patients as per CTA.
  
  
  RESULTS
  A total of 237 consecutive patients underwent pulmonary CTA and had a D-dimer measurement performed. Median D-dimer level was 1007 μg/L and in 11 (5%) patients the pulmonary CT CTA was positive for PE. The ROC curve showed an area under the curve (AUC) of 0.91 (P < 0.0001). Increasing the D-dimer threshold value of 500 μg/L to 1000 μg/L increased the specificity from 8% to 52% without changing the sensitivity.
  
  
  CONCLUSIONS
  Adjusting the D-dimer cut-off value for the emergency department community population and patient age increases the yield and specificity of the ELISA D-dimer assay for the exclusion of PE without reducing sensitivity.
authors: Department of Radiology, Bridgeport Hospital, Yale University School of Medicine, Bridgeport, CT, USA. jvossen1@jhmi.edu
authors: Josephina A
authors: JA
authors: Vossen
authors: Joshua
authors: J
authors: Albrektson
authors: Anirban
authors: A
authors: Sensarma
authors: Scott C
authors: SC
authors: Williams
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D003287:Contrast Media; D004636:Emergency Service, Hospital; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006764:Hospitals, Community; D006801:Humans; D007472:Iohexol; D008297:Male; D008875:Middle Aged; D011655:Pulmonary Embolism / Q000097:blood* / Q000000981:diagnostic imaging; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
chemical_list: D015415:Biomarkers; D003287:Contrast Media; D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; D007472:Iohexol