Presence of white or red cells is significant and indicates mucosal inflammation.
Diagnosis of amoebic colitis requires the presence of Entamoeba histolytica trophozoites containing ingested red cells.
Detection of cysts of Entamoeba histolytica/dispar may represent asymptomatic carriage of the organism.
Cysts or trophozoites of Giardia intestinalis confirm a diagnosis of giardiasis.
Oocysts of Cryptosporidium spp and microsporidia can be identified with special staining techniques; their presence may indicate active infection or carriage.
The presence of characteristic ova can identify infection with:
hookworms, Trichuris and other roundworms (nematodes) eg, Enterobius vermicularis in sticky tape preparations, Ascaris lumbricoides;
flat flukes (trematodes) eg, Fasciola hepatica, Clonorchis Sinensis;
tape worms eg, Taenia saginata, Taenia solium.
Larvae of hookworm or strongyloides can also be present.
Occasionally complete worms are passed, enabling specific identification of the adult worm.