title: Effects of age on the performance of common diagnostic tests for pulmonary embolism.
abstract: OBJECTIVE
  The diagnosis of pulmonary embolism in the elderly is often difficult because of comorbid medical conditions, and perhaps also because diagnostic tests have a lower yield. We analyzed the diagnostic performance of common diagnostic tests for pulmonary embolism in different age groups.
  
  
  METHODS
  We analyzed data from two large studies that enrolled 1,029 consecutive patients presenting to the emergency department with clinically suspected pulmonary embolism. The clinical probability of pulmonary embolism (high [>/=80%], intermediate, or low [</=20%]) was estimated by the treating physician. All patients underwent a sequential diagnostic protocol, including ventilation-perfusion lung scan, measurement of plasma D-dimer level, lower limb venous compression ultrasonography, and pulmonary angiography if the noninvasive work-up was inconclusive.
  
  
  RESULTS
  The prevalence of pulmonary embolism increased progressively, from 12% in patients <40 years of age to 44% in those >/=80 years of age. The positive predictive value of a high clinical probability of pulmonary embolism was greater in the elderly (71% to 78% in those >/=60 years old versus 40% to 64% in those </=59 years old). The sensitivity of D-dimer testing was 100% in all age groups, but its specificity decreased markedly with age, from 67% in those </=40 years old to 10% in those >/=80 years old. The diagnostic yield of lower limb compression ultrasonography was greater in the elderly. The proportion of lung scans that were diagnostic (normal, near-normal, or high probability) decreased from 68% to 42% with increasing age.
  
  
  CONCLUSIONS
  Age affects the performance of common diagnostic tests for pulmonary embolism and should be kept in mind when evaluating patients suspected of having this condition.
authors.affiliation: Department of Internal Medicine (MR, HB), Division of Angiology and Hemostasis, Geneva University Hospital, Geneva, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Righini
authors.forename: C
authors.initials: C
authors.lastname: Goehring
authors.forename: H
authors.initials: H
authors.lastname: Bounameaux
authors.forename: A
authors.initials: A
authors.lastname: Perrier
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D003937:Diagnosis, Differential; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000032:analysis; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011655:Pulmonary Embolism / Q000097:blood / Q000175:diagnosis* / Q000000981:diagnostic imaging; D012306:Risk; D012680:Sensitivity and Specificity; D013557:Switzerland; D014463:Ultrasonography / Q000379:methods; D014692:Ventilation-Perfusion Ratio
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D