Redundant testing contributes to reductions in healthcare system efficiency. The purpose of this study was to: (1) determine if the use of a computerized alert would reduce the number and cost of duplicated Acute Hepatitis Profile (AHP) laboratory tests and (2) assess what patient, test, and system factors were associated with duplication. This study used a quasi-experimental pre- and post-test design to determine the proportion of duplication of the AHP test before and after implementation of a computerized alert intervention. The AHP test was duplicated if the test was requested again within 15 days of the initial test being performed and the result present in the medical record. The intervention consisted of a computerized alert (pop-up window) that indicated to the clinician that the test had recently been ordered. A total of 674 AHP tests were performed in the pre-intervention period and 692 in the postintervention group. In the pre-intervention period, 53 (7.9%) were duplicated and in postintervention, 18 (2.6%) were duplicated (p < .001). The implementation of the alert was shown to significantly reduce associated costs of duplicated AHP tests (p ≤ .001). Implementation of computerized alerts may be useful in reducing duplicate laboratory tests and improving healthcare system efficiency.