True cost estimation of common imaging procedures for cost-effectiveness analysis - insights from a Singapore hospital emergency department

Objectives: There is a lack of clear and consistent cost reporting for cost-effectiveness analysis in radiology. Estimates are often obtained using costing derived from hospital charge records. This study aims to evaluate the accuracy of hospital charge records compared to a Singapore hospital's true diagnostic imaging costs. Methods: A seven-step process involving a bottom-up micro-costing approach was devised and followed to calculate the cost of imaging using actual data from a clinical setting. We retrieved electronic data from a random sample of 96 emergency department patients who had CT brain, CT and X-ray cervical spine, and X-ray lumbar spine performed to calculate the parameters required for cost estimation. We adjusted imaging duration and number of performing personnel to account for variations. Results: Our approach determined the average cost for the following imaging procedures: CT brain (<euro>154.00), CT and X-ray cervical spine (<euro>177.14 and <euro>68.22), and X-ray lumbar spine (<euro>79.85). We found that the true cost of both conventional radiography procedures was marginally higher than the subsidized patient charge, and all costs were slightly lower than the private patient charge except for X-ray lumbar spine (<euro>73.49 vs.<euro>79.85). We identified larger differences in cost for both CT procedures and smaller differences in cost for conventional radiography procedures, depending on the patient's private or subsidized status. For private status, the differences were: CT brain (Min: <euro>194.20; Max: <euro>264.40), CT cervical spine (Min: <euro>219.54; Max: <euro>399.05), X-ray cervical spine (Min: <euro>5.27; Max: <euro>61.94), and X-ray lumbar spine (Min: <euro>6.36; Max: <euro>108.04), while for subsidized status, the differences were: CT brain (Min: <euro>7.56; Max: <euro>62.64), CT cervical spine (Min: <euro>47.02; Max: <euro>132.49), X-ray cervical spine (Min: <euro>15.88; Max: <euro>103.44), and X-ray lumbar spine (Min: <euro>13.66; Max: <euro>149.44). Considering examination duration and the number of personnel engaged in a procedure, there were significant variations in the minimum, average, and maximum imaging costs. Conclusion: There is a modest gap between hospital charges and actual costs, and we must therefore exercise caution and recognize the limitations of utilizing hospital charge records as absolute metrics for costeffectiveness analysis. Our detailed approach can potentially enable more accurate imaging cost determination for future studies.