Clinical microbiology is in the midst of an era of emphasis on rapid test performance and reporting, often through use of automated instrumentation. Results which are generated very rapidly using an automated instrument, but which are not available in the patient's medical record until the following day cannot improve clinical decision making. A number of clinical microbiology laboratories employ computers ranging in size from small personal or microcomputers which are packaged as instrument-based "data management" systems to large laboratory-wide main frame systems which may include on-line interfacing of certain automated microbiology instruments. Results generated by automated instruments offer the greatest potential for rapid result transmission by directly interfacing the microcomputer which controls the instrument's function with the microbiology host computer. Computer generation of reports for use by those outside the laboratory is the final and often most visible step in use of computers in clinical microbiology.