title: The effect of a hepatitis serology testing algorithm on laboratory utilization.
abstract: OBJECTIVE
  Laboratory testing algorithms use patient and laboratory data to identify the optimal testing strategy for patients. Studies have shown that these algorithms can decrease test utilization. Since over-utilization of hepatitis serological tests was suspected, a hepatitis serology testing algorithm was initiated in Ontario, Canada. This study determined the effects of this algorithm on utilization.
  
  
  METHODS
  Population-based retrospective observational study, involving all patients having viral hepatitis serological testing at private laboratories in Ontario, Canada, between July 1991 and December 1999. Prior to the testing algorithm, physicians listed the required specific antigens and antibodies on the test requisition form. In September 1996, the form was changed so that physicians identified the clinical indication--acute hepatitis, chronic hepatitis or immune status testing--for hepatitis serology testing. Therefore, the algorithm introduced a new 'tick-box' to the requisition form. Tests conducted by the laboratory depended upon which indication was chosen. Rates for hepatitis serological testing were calculated using population-based claims data.
  
  
  RESULTS
  Time-series modelling showed that the testing algorithm was associated with a slight but significant increase in the use of hepatitis serology (P < 0.05). The algorithm was associated with an increase of 30 serological tests per 100,000 population per month.
  
  
  CONCLUSIONS
  Introducing a testing algorithm for hepatic viral serology in Ontario did not significantly decrease hepatitis serology utilization and may be associated with a slight, but significant, increase in serology utilization rates.
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Canada. carlv@ohri.ca
authors.forename: Carl
authors.initials: C
authors.lastname: van Walraven
authors.forename: Vivek
authors.initials: V
authors.lastname: Goel
mesh_terms: D000465:Algorithms; D005568:Forms and Records Control; D006525:Hepatitis, Viral, Human / Q000175:diagnosis*; D006801:Humans; D007753:Laboratories / Q000706:statistics & numerical data*; D009864:Ontario; D012189:Retrospective Studies; D012698:Serologic Tests / Q000706:statistics & numerical data*