Macroscopic Examination (cont.)

an advantage in terms of recovery and identification of intestinal protozoa. This advantage (preservation of organisms before distortion or disintegration) is felt to outweigh the limited motility information that might be gained by examining fresh specimens. Each laboratory will have to decide for itself, often basing the decision on the types of procedures ordered by the physicians who use the laboratory service, the test methodologies selected (traditional methods or new immunoassay detection kits), and the lag time between specimen collection and submission to the laboratory. If specimens are received that do not meet specimen requirements for quality, they should be rejected and additional specimens requested.

Freshly passed specimens are necessary for the detection of trophic amebae, flagellates, and ciliates. Examination of liquid specimens must be carried out within 30 min of passage (not 30 min from the time the