Which two tests are commonly used to detect intestinal parasites in stool?

• A. Fecal flotation and fecal sedimentation
• B. Urine culture
• C. Skin scrapings
• D. Fecal exam with flotation for eggs and cysts

Answer: (A)

Detecting intestinal parasites in stool relies on concentrating parasite stages so eggs, cysts, and oocysts can be seen under a microscope. Different parasites shed eggs with different densities, so one method won’t catch everything. Fecal flotation uses a solution with a higher specific gravity than the parasite eggs, making them float to the surface for collection and examination. Fecal sedimentation, on the other hand, relies on gravity to collect heavier eggs in the sediment, which is then examined. Using both techniques together increases the chance of finding a wider range of intestinal parasites in a single sample. Urine culture and skin scrapings are not used for detecting stool parasites, and a flotation exam alone may miss heavier eggs that sedimentation would catch. Therefore, the two tests commonly used are fecal flotation and fecal sedimentation.