Accuracy of technicians and pharmacists in identifying dispensing errors.

The accuracies with which pharmacists and technicians checked medications in a unit dose distribution system were compared. The study was conducted at three large hospitals in Washington State. From August through October 1991, technicians filled unit dose medication drawers and pharmacists verified the accuracy of each fill (pharmacist verification period). From November 1991 through January 1992, technicians who had undergone special training verified the accuracy with which medication drawers were filled by other technicians (technician verification period). For each study period, two error rates were estimated: the frequency with which the pharmacists or technicians identified dispensing errors and the frequency of verification errors identified by the investigators in a final independent check. A total of 143,952 unit doses were dispensed during the pharmacist verification period, of which 49,718 were randomly analyzed for accuracy. A total of 151,721 doses were dispensed during the technician intervention period, of which 55,470 were assessed. The mean +/- S.E. daily rates of dispensing-error identification by pharmacists (0.0125 +/- 0.0069%) and technicians (0.0119 +/- 0.0001) did not differ significantly. While pharmacists overlooked more errors (107) than technicians (50), the percentage of such missed errors classified as potentially serious did not differ significantly between the groups (25.2% versus 32.0%, respectively). Pharmacy technicians who underwent special training were able to verify medications in a unit dose distribution system without compromising the accuracy of dispensing.