Entamoeba histolytica

Polymorphonuclear leukocytes in fecal smear (trichrome stain, oil immersion). The larger the number of such "pus cells," the less likely is their presence to be confusing to the microscopist. These cells should not be confused with amebae, although their sizes may be similar; the ratio of nuclear material to cytoplasm is 1:1 in leukocytes, whereas in Entamoeba histolytica this ratio is 1:2 or 1:3. Although there are two to four nuclear segments in leukocytes, the narrow chromatic bands joining them may not be visible. Nuclear segments do not resemble nuclei of amebae, and there is no central mass to be mistaken for a karyosome.