title: Prospective evaluation of the ability of clinical scoring systems and physician-determined likelihood of appendicitis to obviate the need for CT.
abstract: OBJECTIVE
  To determine whether clinical scoring systems or physician gestalt can obviate the need for computed tomography (CT) in patients with possible appendicitis.
  
  
  METHODS
  Prospective, observational study of patients with abdominal pain at an academic emergency department (ED) from February 2012 to February 2014. Patients over 11 years old who had a CT ordered for possible appendicitis were eligible. All parameters needed to calculate the scores were recorded on standardised forms prior to CT. Physicians also estimated the likelihood of appendicitis. Test characteristics were calculated using clinical follow-up as the reference standard. Receiver operating characteristic curves were drawn.
  
  
  RESULTS
  Of the 287 patients (mean age (range), 31 (12-88) years; 60% women), the prevalence of appendicitis was 33%. The Alvarado score had a positive likelihood ratio (LR(+)) (95% CI) of 2.2 (1.7 to 3) and a negative likelihood ratio (LR(-)) of 0.6 (0.4 to 0.7). The modified Alvarado score (MAS) had LR(+) 2.4 (1.6 to 3.4) and LR(-) 0.7 (0.6 to 0.8). The Raja Isteri Pengiran Anak Saleha Appendicitis (RIPASA) score had LR(+) 1.3 (1.1 to 1.5) and LR(-) 0.5 (0.4 to 0.8). Physician-determined likelihood of appendicitis had LR(+) 1.3 (1.2 to 1.5) and LR(-) 0.3 (0.2 to 0.6). When combined with physician likelihoods, LR(+) and LR(-) was 3.67 and 0.48 (Alvarado), 2.33 and 0.45 (RIPASA), and 3.87 and 0.47 (MAS). The area under the curve was highest for physician-determined likelihood (0.72), but was not statistically significantly different from the clinical scores (RIPASA 0.67, Alvarado 0.72, MAS 0.7).
  
  
  CONCLUSIONS
  Clinical scoring systems performed equally well as physician gestalt in predicting appendicitis. These scores do not obviate the need for imaging for possible appendicitis when a physician deems it necessary.
authors.affiliation: BerbeeWalsh, Department of Emergency Medicine, University of Wisconsin-Madison, Wisconsin, USA.
authors.forename: Sean K
authors.initials: SK
authors.lastname: Golden
authors.affiliation: BerbeeWalsh, Department of Emergency Medicine, University of Wisconsin-Madison, Wisconsin, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Harringa
authors.affiliation: Department of Radiology, University of Wisconsin-Madison, Wisconsin, USA.
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pickhardt
authors.affiliation: Department of Emergency Medicine, University of Colorado School of Medicine, Denver, Colorado, USA.
authors.forename: Alexander
authors.initials: A
authors.lastname: Ebinger
authors.affiliation: BerbeeWalsh, Department of Emergency Medicine, University of Wisconsin-Madison, Wisconsin, USA.
authors.forename: James E
authors.initials: JE
authors.lastname: Svenson
authors.affiliation: Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Ying-Qi
authors.initials: YQ
authors.lastname: Zhao
authors.affiliation: Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Zhanhai
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Westergaard
authors.affiliation: Department of Medicine, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Ehlenbach
authors.affiliation: BerbeeWalsh, Department of Emergency Medicine, University of Wisconsin-Madison, Wisconsin, USA Department of Radiology, University of Wisconsin-Madison, Wisconsin, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Repplinger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000000981:diagnostic imaging*; D002648:Child; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
keywords: abdomen- non trauma, gastro-intestinal; clinical assessment, effectiveness; imaging, CT/MRI