title: Surgical site infections: might a longer locally defined T time affect the benchmarking?
abstract: BACKGROUND
  A local surgical site infection surveillance system (LS System) was established in 1998 at our teaching hospital. The aims of this article were to compare locally defined cut-points with the NNIS System T times, and to evaluate the effectiveness of different cut-points in identifying procedures at high risk for infection.
  
  
  METHODS
  The LS System T times were compared to those reported by the NNIS System. Procedures and surgical site infections (SSIs) were stratified according to two infection risk index (IRI) scores calculated by using the two cut-points. The effectiveness of the two IRI scores in predicting SSIs was assessed by receiver operating characteristic (ROC) analysis.
  
  
  RESULTS
  We have found a longer T time in three procedures categories compared to those reported by the NNIS System (GAST, OGIT, and XLAP). The LS System risk index predicted SSIs better than did the NNIS System risk index only in other digestive category, with areas under ROC curve: being, respectively of 71.1% (95% CI, 60.9, 81.3) and 63.1% (95% CI, 54.0, 72.2).
  
  
  CONCLUSIONS
  The use of the NNIS System T time is suitable in our local SSI surveillance system because it does not significantly affect the benchmarking.
authors.affiliation: Infectious Disease and Public Health Institute, Chair of Hygiene, Faculty of Medicine, Università Politecnica delle Marche, Ancona, Italy. e.prospero@univpm.it
authors.forename: Emilia
authors.initials: E
authors.lastname: Prospero
authors.forename: Pamela
authors.initials: P
authors.lastname: Barbadoro
authors.forename: Isidoro
authors.initials: I
authors.lastname: Annino
authors.forename: Marcello Mario
authors.initials: MM
authors.lastname: D'Errico
mesh_terms: D019985:Benchmarking / Q000379:methods / Q000706:statistics & numerical data; D013505:Digestive System Surgical Procedures / Q000706:statistics & numerical data*; D006801:Humans; D017053:Infection Control / Q000379:methods; D007813:Laparotomy / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D018571:Sentinel Surveillance; D013530:Surgical Wound Infection / Q000453:epidemiology / Q000517:prevention & control*; D013997:Time Factors