title: [Age-adjusted D-dimer cut-offs to diagnose thromboembolic events: validation in an emergency department].
abstract: BACKGROUND
  In elderly patients, an unspecific increase of fibrin degradation products in blood is observed. Thus, the D-dimer test to rule out thromboembolic events has a high false-positive rate in elderly patients. Our aim was to validate an age-adjusted D-dimer cut-off and to assess its utility in elderly patients.
  
  
  METHODS
  In a retrospective cohort of outpatients (n = 1033) presenting to our emergency department with suspected acute pulmonary embolism and/or deep vein thrombosis (PE/DVT), age-adjusted D-dimer cut-off values were derived using receiver operating characteristic (ROC) curve analysis. Subsequently, the proportion of patients with normal D-dimer and false-negative test results, respectively, and the number needed-to-test (NNT) were compared for conventional and age-adjusted cut-off values.
  
  
  RESULTS
  Using the conventional cut-off of 0.5 mg/dl, PE/DVT could be excluded in 68 % of patients, whereas the age-adjusted cut-off [(age × 0.016) mg/l] ruled out 77 % of patients. Particularly in patients > 70 years, the negative prediction accuracy of excluding a PE/DVT increased explicitly. The failure rate of the age-adjusted cut-off value was 0.8 % (95 % confidence interval 0.3-1.6 %).
  
  
  CONCLUSIONS
  The age-adjusted D-dimer cut-off point increases the proportion of older patients, in whom an acute thromboembolic event can be excluded.
authors.affiliation: Medizinische Klinik D, Abteilung für Allg. Innere Medizin, Nephrologie und Rheumatologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, 48149, Münster, Deutschland.
authors.forename: N
authors.initials: N
authors.lastname: Verma
authors.forename: P
authors.initials: P
authors.lastname: Willeke
authors.forename: P
authors.initials: P
authors.lastname: Bicsán
authors.forename: P
authors.initials: P
authors.lastname: Lebiedz
authors.forename: H
authors.initials: H
authors.lastname: Pavenstädt
authors.forename: P
authors.initials: P
authors.lastname: Kümpers
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D004636:Emergency Service, Hospital; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D061366:Numbers Needed To Treat; D011237:Predictive Value of Tests; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis; D012372:ROC Curve; D012016:Reference Values; D012189:Retrospective Studies; D013923:Thromboembolism / Q000097:blood* / Q000175:diagnosis*; D020246:Venous Thrombosis / Q000097:blood / Q000175:diagnosis
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D