Is used in the diagnosis of Giardia lamblia and Strongyloides stercoralis ▪ Giardia’s “falling leaf” motility is rarely seen; Strongyloides larvae are very motile ▪ Centrifugation of the specimen before examination is important ▪ If the specimen cannot be completely examined within 2 hr after it is taken, any remaining material should be preserved in 5% to 10% formalin.