For E. coli, E. hartmanni, E. polecki, E. nana, and I. buetschlii, identification is made by observing cysts and/or trophozoites in stool specimens, both concentrated wet mounts and permanent stained smears. Identification of E. gingivalis is made by the finding of trophozoites in scrapings of the gums and teeth. They may also be found in sputum in rare occasions. As such, it is important to differentiate them from the morphologically-similar trophozoites of E. histolytica, which may be found in sputum from pulmonary abscesses.