Development and implementation of cost-effective guidelines in the laboratory investigation of diarrhea in a community hospital

Background: Fecal cultures are often inappropriately requested in the investigation of diarrhea. Objectives: To develop and determine the efficacy of practice guidelines for the ordering and processing of stool cultures that are submitted for the diagnosis of community-acquired diarrhea. Methods: The results of stool cultures that were submitted to the microbiology laboratory of a tertiary care nonteaching community hospital were retrospectively reviewed. Following the implementation of guidelines, the efficacy was evaluated by comparison of fecal culture results in a prospective manner. Results: Analysis of results of stool cultures that were obtained from 3072 patients during a 3-year period revealed that (1) the sensitivity (40%) and predictive value (20%) of finding neutrophils in smear preparations were too low to be clinically useful, (2) routine cultures from patients with nosocomial diarrhea were uniformly negative, and (3) multiple specimens from a patient rarely provided additional information. Based on these findings, new guidelines were developed and implemented with the cooperation of clinical staff. Three-month follow-up results showed that the total number of specimens, the number of specimens from patients with nosocomial diarrhea, and multiple specimens declined by 37.7%, 70.6%, and 50%, respectively. However, the isolation rate of pathogens increased from 11.7% to 18.7%. Conclusions: The application of practice guidelines that include elimination of smear examination of rectal swabs, exclusion of routine cultures from patients with nosocomial diarrhea, and rejection of repeated cultures can result in significant cost savings without adversely affecting patient care.