Objective To quantify the rate of preventable duplication of imaging studies in the Emergency Department. Previously, to estimate potential savings from the Health Information Exchange, figures used to be based on expert opinion, as the actual rate of redundant imaging is unknown.

Materials and methods We prospectively quantified the frequency of duplicate CT scans in tertiary care and community hospital emergency departments (ED) through a short questionnaire at the time the studies were ordered.

Results During the study period, 9246 CT scans were performed with a preventable duplicate rate of 0.42%. Both sites had equivalent rates of preventable duplicates.

Discussion and conclusions We used two EDs to quantify the rate of preventable duplicate CT scans ordered. Our results demonstrate that only 0.4% of CT scans performed in our EDs are preventable duplicates. Our rate of preventable duplicate studies was much lower than what experts and emergency practitioners suspected, which suggests that potential cost savings from elimination of preventable duplicates may also be much lower than currently estimated.