title: Systematic quantitative overviews of the literature to determine the value of diagnostic tests for predicting acute appendicitis: study protocol.
abstract: BACKGROUND
  Suspected acute appendicitis is the most frequent cause for emergency operations in visceral surgery worldwide. In approximately twenty percent of all cases however, the diagnosis is incorrect and patients undergo surgery without having acute appendicitis. Operations of bland appendices put patients at risk and entail a serious waste of resources. Several highly accurate tests have been introduced to diagnose acute appendicitis. The false positive rate however, has not changed over the last twenty years. Given the variation that exists in both practice and research, the uncertainty regarding the quality of the underlying evidence, there is a clear need for comprehensive, systematic and quantitative overviews of the diagnostic value of the various tests purported to be predictive of acute appendicitis.
  
  
  METHODS
  Literature will be identified searching general bibliographic databases (MEDLINE and EMBASE), specialist computer databases (DARE, Cochrane Database of Systematic Reviews, conference proceedings, MEDION, SCISEARCH, BIOSIS) without language restrictions. We will contact experts and the manufacturers of tests. Hand-searching will complete our searches. Identified articles will be selected according to populations, tests, outcomes and study design. Papers meeting the selection criteria will be appraised to rate their methodological quality. Analysis will include exploration of heterogeneity in results. We will conduct meta-analyses to generate summary estimates of test accuracy measures and summary ROC curves where appropriate. If meta-analysis is considered to be inappropriate, we will describe the identified evidence in the context of appraised quality.
  
  
  CONCLUSIONS
  These reviews should lead to formulation of recommendations for current practice and future research.
authors.affiliation: Horten Centre, University of Zurich, Switzerland. lucas.bachmann@evimed.ch
authors.forename: Lucas M
authors.initials: LM
authors.lastname: Bachmann
authors.forename: Dominique B
authors.initials: DB
authors.lastname: Bischof
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Bischofberger
authors.forename: Marco G
authors.initials: MG
authors.lastname: Bonani
authors.forename: Franziska M
authors.initials: FM
authors.lastname: Osann
authors.forename: Johann
authors.initials: J
authors.lastname: Steurer
mesh_terms: D001064:Appendicitis / Q000175:diagnosis*; D003938:Diagnostic Techniques, Digestive System; D006801:Humans; D015201:Meta-Analysis as Topic; D012196:Review Literature as Topic