Does the computerized display of charges affect inpatient ancillary test utilization?

Background: The computerized display of charges for ancillary tests in outpatients has been found to affect physician-ordering behavior, but this issue has not been studied in inpatients. Objective: To assess whether the computerized display of charges for clinical laboratory or radiological tests affected physician-ordering behavior. Patients and Methods: Two prospective controlled trials, randomized by patient, were performed. Each trial included all medical and surgical inpatients at 1 large teaching hospital during 4 and 7 months: 3536 intervention and 3554 control inpatients in the group with clinical laboratory tests, and 8728 intervention and 8653 control inpatients in the group with radiological tests. The intervention consisted of the computerized display of charges for tests at the time of ordering. Main Outcome Measures: The number of clinical laboratory and radiological tests ordered per admission and the charges for these tests. Results: For the clinical laboratory tests, during a 4-month study period, patients in the intervention group had 4.5% fewer tests ordered, and the total charges for these tests were 4.2% lower, although neither difference was statistically significant. Compared with historical controls from the same 4-month period a year before, the charges for the tests per admission had decreased 13.3%, but the decrease was temporally correlated with a restriction of future ordering of tests, and not with the introduction of the display of charges. For the radiological tests, during a 7-month period, the intervention group had almost identical numbers of tests ordered and charges for these tests. Conclusions: The computerized display of charges had no statistically significant effect on the number of clinical laboratory tests or radiological procedures ordered or performed, although small trends were present for clinical laboratory tests. More intensive interventions may be needed to affect physician test utilization.