Cost per case mix index–adjusted hospital day as a measure of effective laboratory utilization efforts in a growing academic medical center

Objectives: Traditional laboratory utilization measures are unable to detect the results of small-scale utilization improvement efforts in a background of rising patient volumes and acuity. However, accurate assessment is necessary to document effectiveness of these efforts. Methods: Test menu changes, physician education, and laboratory utilization feedback were used to address costs and overused tests. Effectiveness was evaluated using cost/case mix index (CMI)–adjusted hospital day and inpatient tests/CMI-adjusted discharge. These metrics were compared with the more traditional measures of cost/ test and inpatient tests/discharge. Results: Cost/CMI-adjusted hospital day and inpatient tests/CMI-adjusted discharge better demonstrated the impact of utilization improvement efforts compared with more traditional measures because they account for changes in patient volume and acuity. Conclusions: Cost/CMI-adjusted hospital day and tests/CMI-adjusted discharge show the effectiveness of laboratory utilization efforts despite increasing patient volume and acuity.