Cost analysis of the Auto Microbic system urine identification card

The AutoMicrobic system (Vitek Systems, Inc., Hazelwood, Mo.) is a fully automated, computerized instrument. One of the most thoroughly studied aspects of the system is its ability to identify and quantify of nine most common urinary tract pathogens. The major advantages of the AutoMicrobic system are that the results of urine cultures are available in a fraction of the time required by conventional methods and that samples can be processed with fewer man-hours. Although the specificity, sensitivity, and reliability of the system have been amply described in the literature, only one study combines these aspects with a cost analysis (D. P. Nicholson and J. A. Koepke, J. Clin. Microbiol. 10:823-833, 1979). Because one of the major considerations that microbiology laboratory directors must face is the cost-effectiveness of instruments, we studied the relative cost of the system as compared with that of conventional methods. Our findings indicated that the instrument provided valuable savings in technologist and turnaround time. These advantages were most easily realized in processing positive urine specimens. For negative urine specimens, the savings in technologist time were cancelled by the cost of the consumable supplies, which greatly exceeded the cost of supplies for conventional methods. This disadvantage might be ameliorated by efficient and effective screening methods to exclude those urine specimens that are most probably negative.