Objective: To evaluate the utility of stool water analysis in the management of patients with chronic diarrhea.
Design: Retrospective analysis of 6 years of experience.
Setting: A specialized laboratory in a major referral center.
Patients: 325 patients with diarrhea who were referred for stool chemistry analysis. Fecal analysis was requested by many internists and gastroenterologists. Patient records were reviewed to establish the final and most likely cause of diarrhea.
Results: One third of patients provided samples that were inappropriate for analysis, but data from 202 persons were available. The usefulness of the general separation of cases of chronic diarrhea into those in which patients had predominantly osmotic pathophysiologies and those in which patients had predominantly secretory pathophysiologies was confirmed, but overlap and intra-individual variability limited the usefulness of this approach in individual patients. Thirty-five patients (17%) had a diagnosis of factitial diarrhea (30 because of laxative use and 5 because of fluid added to stools).
Conclusions: Among selected subpopulations, the chemical analysis of fresh stools has a role in the evaluation of obscure examples of chronic diarrhea. It is especially useful in identifying factitial diarrhea.