title: The incidence of un-indicated preoperative testing in a tertiary academic ambulatory center: a retrospective cohort study.
abstract: BACKGROUND
  Despite existing evidence and guidelines advocating for appropriate risk stratification, ambulatory surgery in low-risk patients continues to be accompanied by a battery of routine tests prior to surgery. Using a single-center retrospective cohort study, we aimed to quantify the incidence of un-indicated preoperative testing in an academic ambulatory center by utilizing recommendations by the recently developed American Society of Anesthesiology (ASA) "Choosing Wisely" Top-5 list.
  
  
  METHODS
  We utilized data from the EPIC medical records of 3111 patients who had ambulatory surgery at the Hospital of the University of Pennsylvania during a 6-month period. Data were abstracted from laboratory studies- complete blood count, electrolyte panel, coagulation studies, and cardiac studies-stress test, and echocardiogram obtained within 30 days prior to surgery. Preoperative tests obtained from each patient were categorized into "indicated" (ASA ≥ 3) and "un-indicated" (ASA 1 and 2) tests, and percentages were reported.
  
  
  RESULTS
  During the study period, 52.9 % (95 % confidence interval (CI) 37.6-66.4) of all patients had at least one un-indicated laboratory test performed preoperatively. Further analysis revealed variation in the incidence of preoperative ordering between tests; 73 % of all complete blood counts (CBCs), 70 % of all metabolic panels, and 49 % of all coagulation studies were considered un-indicated by "Top-5 List" criteria. Stated differently, of the patients included in the sample, 51 % of patients received an un-indicated CBC, 41 % an un-indicated metabolic panel, and 16 % un-indicated coagulation studies. Twelve percent of "any un-indicated preoperative test" were obtained from ASA 1 healthy patients. Of the 587 patients less than 36 years old, 331 (56 %) had at least one test that was deemed un-indicated. Forty-one patients had either an echocardiogram or stress test ordered and performed within 30 days of surgery. Of these, eight (19.5 %) studies were un-indicated as determined by chart review.
  
  
  CONCLUSIONS
  The incidence of ordering "at least one un-indicated preoperative test" in low-risk patients undergoing low-risk surgery remains high even in academic tertiary institutions. In the emerging era of optimizing patient safety and financial accountability, further studies are needed to better understand the problem of overuse while identifying modifiable attitudes and institutional influences on perioperative practices among all stakeholders involved. Such information would drive the development of feasible interventions.
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street Dulles 680, Philadelphia, PA 19104 USA.
authors.forename: Onyi C
authors.initials: OC
authors.lastname: Onuoha
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street Dulles 680, Philadelphia, PA 19104 USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Hatch
authors.affiliation: Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania USA.
authors.forename: Todd A
authors.initials: TA
authors.lastname: Miano
authors.affiliation: Department of Anesthesiology and Critical Care, Perelman School of Medicine, Senior Scholar, Leonard Davis Institute, University of Pennsylvania, Philadelphia, Pennsylvania USA.
authors.forename: Lee A
authors.initials: LA
authors.lastname: Fleisher
keywords: ASA (American Society of Anesthesiology); Ambulatory; Laboratory test (complete blood count, metabolic panel, coagulation studies); Low risk; Preoperative testing; Routine; Un-indicated