Comparative evaluation of a modified zinc sulfate flotation technique.

A modified zinc sulfate flotation technique using Formalinized fecal specimens (F-ZnSO4) was compared to the Formalin-ether (FE) concentration method for the laboratory diagnosis of intestinal parasites. Many laboratories have difficulty storing, using, and disposing of either and need a procedure for concentrating fecal specimens which does not require ether. Comparative data were obtained for the recovery of protozoan cysts and helminth eggs and larvae from feces preserved in Formalin less than and longer than 1 month. Whereas the FE method was found generally to be more efficient, F-ZnSO4 was apparently more effective for the recovery of some species of parasites. F-ZnSO4 was not satisfactory for recovery of schistosome eggs. We conclude that, except for schistosomes, F-ZnSO4 compares favorably to the FE method for detecting infections of clinical significance.