title: Out-of-hospital stroke screen accuracy in a state with an emergency medical services protocol for routing patients to acute stroke centers.
abstract: OBJECTIVE
  Emergency medical services (EMS) protocols, which route patients with suspected stroke to stroke centers, rely on the use of accurate stroke screening criteria. Our goal is to conduct a statewide EMS agency evaluation of the accuracies of the Cincinnati Prehospital Stroke Scale (CPSS) and the Los Angeles Prehospital Stroke Screen (LAPSS) for identifying acute stroke patients.
  
  
  METHODS
  We conducted a retrospective study in North Carolina by linking a statewide EMS database to a hospital database, using validated deterministic matching. We compared EMS CPSS or LAPSS results (positive or negative) to the emergency department diagnosis International Classification of Diseases, Ninth Revision codes. We calculated sensitivity, specificity, and positive and negative likelihood ratios for the EMS diagnosis of stroke, using each screening tool.
  
  
  RESULTS
  We included 1,217 CPSS patients and 1,225 LAPSS patients evaluated by 117 EMS agencies from 94 North Carolina counties. Most EMS agencies contributing data had high annual patient volumes and were governmental agencies with nonvolunteer, emergency medical technician-paramedic service level providers. The CPSS had a sensitivity of 80% (95% confidence interval [CI] 77% to 83%) versus 74% (95% CI 71% to 77%) for the LAPSS. Each had a specificity of 48% (CPSS 95% CI 44% to 52%; LAPSS 95% CI 43% to 53%).
  
  
  CONCLUSIONS
  The CPSS and LAPSS had similar test characteristics, with each having only limited specificity. Development of stroke screening scales that optimize both sensitivity and specificity is required if these are to be used to determine transport diversion to acute stroke centers.
authors.affiliation: Department of Emergency Medicine, Carolinas Medical Center, Charlotte, NC. Electronic address: aasimos@carolinas.org.
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Asimos
authors.affiliation: Dickson Advanced Analytics Group, Carolinas Heath Care System, Charlotte, NC.
authors.forename: Shana
authors.initials: S
authors.lastname: Ward
authors.affiliation: Department of Emergency Medicine, School of Medicine, University of North Carolina, Chapel Hill, NC.
authors.forename: Jane H
authors.initials: JH
authors.lastname: Brice
authors.affiliation: Department of Epidemiology, School of Public Health, University of North Carolina, Chapel Hill, NC.
authors.forename: Wayne D
authors.initials: WD
authors.lastname: Rosamond
authors.affiliation: Department of Neurology, Duke University and Durham VA Medical Center, Durham, NC.
authors.forename: Larry B
authors.initials: LB
authors.lastname: Goldstein
authors.affiliation: Mecklenburg EMS Agency, Charlotte, NC.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Studnek
mesh_terms: D000368:Aged; D002985:Clinical Protocols; D003661:Decision Support Techniques; D004632:Emergency Medical Services / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D008297:Male; D009657:North Carolina / Q000453:epidemiology; D010043:Outcome and Process Assessment, Health Care; D012680:Sensitivity and Specificity; D020521:Stroke / Q000175:diagnosis* / Q000628:therapy