The formalin-ether (ethyl acetate) concentration procedure is used to demonstrate what?

The formalin-ether (ethyl acetate) concentration procedure is specifically designed to concentrate and identify protozoan cysts and helminth eggs from fecal samples. This method involves mixing a fecal specimen with formalin to preserve the protozoa and helminths while also killing any motile forms. Ether or ethyl acetate is then added to separate the organic material from the aqueous phase, allowing for the extraction of eggs and cysts which are then concentrated in a sediment that can be examined microscopically.

This technique is particularly effective for recovering cysts from protozoa such as Giardia lamblia and eggs from various helminths, such as Ascaris lumbricoides or hookworm species. The formalin-ether concentration is a common diagnostic procedure in parasitology due to its efficacy in producing a clearer view of these structures, aiding in accurate identification and diagnosis of parasitic infections.

Other options, like the motility of helminth larvae or the observation of amoebic pseudopods, are not characteristics targeted in this concentration technique. Similarly, while trophozoites may be observed in other types of preparations, they are not the focus of this concentration process, which is aimed at stationary forms preserved for identification