title: Defining the positive tilt test: a study of healthy adults with moderate acute blood loss.
abstract: OBJECTIVE
  To define a set of orthostatic vital signs that minimize the frequency of false-positives among healthy individuals while maximizing sensitivity in detecting acute moderate blood loss and to determine the sensitivity and specificity of this optimized tilt test in detecting acute moderate blood loss.
  
  
  METHODS
  Postural vital signs were recorded in a standardized manner before and after 450-mL phlebotomy. Paired comparisons were done for a variety of criteria for a positive tilt test using receiver-operating characteristic curves.
  
  
  METHODS
  Three hundred forty-five healthy euvolemic adult volunteer blood donors were tested at three community blood donation centers over a one-year period. Subjects were prospectively divided into group 1 (less than age 65; 301) and group 2 (age 65 or older; 44).
  
  
  RESULTS
  For each combination of pulse and blood pressure in group 1, a change in pulse alone had the same or higher sensitivity with at least the same specificity. Pulse alone was similarly superior in group 2 compared with previously published combinations of pulse and blood pressure. Even the optimized tilt test had limited sensitivity in detecting acute moderate blood loss with high specificity.
  
  
  CONCLUSIONS
  In applying the tilt test to young adults without cardiovascular disease, pulse measurement usually is all that is necessary.
authors.affiliation: Division of Emergency Medicine, University of Florida Health Science Center, Jacksonville.
authors.forename: M D
authors.initials: MD
authors.lastname: Witting
authors.forename: R L
authors.initials: RL
authors.lastname: Wears
authors.forename: S
authors.initials: S
authors.lastname: Li
mesh_terms: D000208:Acute Disease; D000328:Adult; D000367:Age Factors; D000368:Aged; D001782:Blood Donors; D001794:Blood Pressure; D001810:Blood Volume; D001815:Bloodletting / Q000009:adverse effects*; D005189:False Positive Reactions; D006801:Humans; D007024:Hypotension, Orthostatic / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D008875:Middle Aged; D011187:Posture; D011446:Prospective Studies; D011674:Pulse; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index