Comparison of formalin-ethyl ether sedimentation, formalin-ethyl acetate sedimentation, and zinc sulfate flotation techniques for detection of intestinal parasites.

Formalin-ethyl ether sedimentation, Formalin-ethyl acetate sedimentation, and zinc sulfate flotation techniques were compared using over 250 clinical parasitology specimens. Fifty positive specimens were identified, and a variety of parasites, including amoebae, flagellates, cestodes, nematodes, and trematodes, were encountered. The Formalin-ether and Formalin-ethyl acetate sedimentation procedures gave identical results for the detection of cysts, ova, and larvae, and these methods offered an advantage over the flotation procedure for the detection of selected ova. However, the zinc sulfate procedure was more effective for the detection of protozoan cysts, Hymenolepis nana, and hookworm eggs. The results indicate that the Formalin-ethyl acetate procedure provides a suitable alternative to the Formalin-ether method, and they demonstrate the value of using both flotation and sedimentation procedures in the analysis of fecal specimens for parasites.