The frequency and cost of redundant laboratory testing for transferred ED patients

Introduction Health care costs continue to rise; reducing unnecessary laboratory testing may reduce costs. The goal of this study was to calculate the frequency and estimated costs of repeat normal laboratory testing of patients transferred to a tertiary care emergency department (ED). Methods This was a retrospective cohort study of patients transferred to a tertiary care, level -one trauma ED with an annual census of 90,000 patients. We defined "repeat normal testing" as laboratory tests repeated within 8 hours that were normal at both the sending hospital and the receiving tertiary care hospital. We estimated the charges associated with repeat normal laboratory testing for 11 common ED tests: basic metabolic panel, calcium, magnesium, phosphorus, lipase, thyroids stimulating hormone, prothrombin time, partial thromboplastin time, complete blood count, liver function test, and urine analysis. Results Two hundred thirty-two patients were transferred to the receiving tertiary care hospital from within the hospital's network from May 1, 2011, to October 31, 2011. On average, each transferred patient had one repeat normal laboratory test (245/232 = 1.06). For all laboratory tests, repeat normal testing occurred at least 40% of the time. Extrapolating the data, the total yearly estimated charges of all repeat normal testing was $580,526. Conclusion This study provides the first analysis of the frequency of repeated laboratory testing for all transferred ED patients and indicates that repeat normal testing represents a significant cost. Future research needs to determine if such repeat testing is indeed clinically appropriate or redundant.