Potential impact of rapid microbiology tests in the prospective payment era.

The potential impact of rapid microbiology tests in the prospective payment era is complex and difficult to assess. Although several of the newer methods have been shown to speed detection, isolation, and susceptibility testing of clinical isolates, many of these improvements come only at an additional cost to the microbiology laboratory. Decisions as to whether it is cost-effective to implement these tests may necessitate an analysis at three separate but interdependent levels: level 1--laboratory costs, level 2--hospital costs, and level 3--morbidity and mortality. Within each of these levels, cost offsets associated with a variety of factors may be identifiable. These factors should be carefully evaluated before implementing new methodologies in the microbiology laboratory.