Evaluation of direct wet mount parasitological examination of preserved fecal specimens.

A retrospective study covering a 12-year period was performed to determine the contribution of the direct wet mount microscopic examination to the identification of intestinal parasites in preserved fecal material. It was determined that each of 898 specimens contained at least one parasite when processed by the direct wet mount, concentration, and trichrome staining procedures. Of these procedures, the direct wet mount examination was solely responsible for the identification of 45 (2.9%) of 1,581 parasites identified. This is in contrast to the 15.1 and 12.5% which were found exclusively by the concentration and trichrome methods, respectively. These percentages may vary, depending on the prevalence of parasites and the stages present in the stool specimen.