Several recently published studies of schistosomiasis japonicum infection have used the results of a single stool examination to classify patients as being infected or not. Wiest and others cite unpublished studies to point out that infected individuals may not be detected using the Kato-Katz technique. However, the fact that passage of Schistosoma japonicum eggs in stool is sporadic, and that multiple stool examinations increase sensitivity, has also been clearly demonstrated in published studies. Only 15% of patients in the Philippines with late S. japonicum infection were diagnosed on the basis of a single stool exam. Rectal biopsy is a more sensitive method of detecting eggs but cannot be performed routinely on large numbers of patients. Conclusions from studies, where the basis for including or excluding patients is false, cannot be accepted.