infectious diseases
Giardiasis
Diagnosis of Giardiasis
Enzyme immunoassay for antigen or molecular test for parasite DNA in stool Microscopic examination of stool Enzyme immunoassay to detect parasite antigen in stool is more sensitive than microscopic examination. Characteristic trophozoites or cysts in stool are diagnostic, but parasite excretion is intermittent and at low levels during chronic infections. Thus, microscopic diagnosis may require repeated stool examinations. Sampling of the upper intestinal contents can also yield trophozoites but is seldom necessary. Molecular tests for parasite DNA in stool are available. 