Laboratory cost and utilization containment

The authors analyzed laboratory costs and utilization in 3,771 cases of Medicare inpatients admitted to a New England academic medical center ("the Hospital") from October 1, 1989 to September 30, 1990. The data were derived from the Hospital's Decision Resource System comprehensive data base. The authors established a historical reference point for laboratory costs as a percentage of total inpatient costs using 1981-82 Medicare claims data and cost report information. Inpatient laboratory costs were estimated at 9.5% of total inpatient costs for pre-Diagnostic Related Groups (DRGs) Medicare discharges. Using this reference point and adjusting for the Hospital's 1990 case mix, the "expected" laboratory cost was 9.3% of total cost. In fact, the cost averaged 11.5% (i.e., 24% above the expected cost level), and costs represented an even greater percentage of DRG reimbursement at 12.9%. If we regard the reimbursement as a total cost target (to eliminate losses from Medicare), then that 12.9% is 39% above the "expected" laboratory proportion of 9.3%. The Hospital lost an average of $1,091 on each DRG inpatient. The laboratory contributed 29% to this loss per case. Compared to other large hospitals, the Hospital was slightly (3%) above the mean direct cost per on-site test and significantly (58%) above the mean number of inpatient tests per inpatient day compared to large teaching hospitals. The findings suggest that careful laboratory cost analyses will become increasingly important as the proportion of patients reimbursed in a fixed manner grows. The future may hold a prospective zero-based laboratory budgeting process based on predictable patterns of DRG admissions or other fixed-reimbursement admission and laboratory utilization patterns.