Dissecting Costs of CT Study: Application of TDABC (Time-driven Activity-based Costing) in a Tertiary Academic Center

The lack of understanding of the real costs (not charge) of delivering healthcare services poses tremendous challenges in the containment of healthcare costs. In this study, we applied an established cost accounting method, the time-driven activity-based costing (TDABC), to assess the costs of performing an abdomen and pelvis computed tomography (AP CT) in an academic radiology department and identified opportunities for improved efficiency in the delivery of this service.

The study was exempt from an institutional review board approval. TDABC utilizes process mapping tools from industrial engineering and activity-based costing. The process map outlines every step of discrete activity and duration of use of clinical resources, personnel, and equipment. By multiplying the cost per unit of capacity by the required task time for each step, and summing each component cost, the overall costs of AP CT is determined for patients in three settings, inpatient (IP), outpatient (OP), and emergency departments (ED).

The component costs to deliver an AP CT study were as follows: radiologist interpretation: 40.1%; other personnel (scheduler, technologist, nurse, pharmacist, and transporter): 39.6%; materials: 13.9%; and space and equipment: 6.4%. The cost of performing CT was 13% higher for ED patients and 31% higher for inpatients (IP), as compared to that for OP. The difference in cost was mostly due to non-radiologist personnel costs.

Approximately 80% of the direct costs of AP CT to the academic medical center are related to labor. Potential opportunities to reduce the costs include increasing the efficiency of utilization of CT, substituting lower cost resources when appropriate, and streamlining the ordering system to clarify medical necessity and clinical indications.