Trematode eggs are typically found in which part of a fecal sample?

• A. Flotation layer
• B. In the sediment
• C. In the urine
• D. In the sediment of a prepared sample

Answer: (D)

Trematode eggs are relatively dense and don’t reliably float in standard flotation solutions. In fecal exams, we use a sedimentation or concentrating method, which pulls the heavy eggs down into the sediment. When you prepare and examine a sedimented sample, that concentrated sediment on the slide is where trematode eggs are most likely to be found. Urine is not relevant for a fecal exam, and stating the sediment of a prepared sample specifically reflects the common practice of examining the concentrated sediment after processing.