Mobile Site ›

Detection of Intestinal Parasites


Receive notification when new Hot Topics are published:

Diagnosis of Giardiasis

Slide 25

March 2009

Diagnosis of giardiasis can be performed in a number of ways. As I’ve shown you previously, Light microscopy with stool Ova and parasite examination may detect the cyst and trophozoite stages. However, cysts are shed only periodically, and six or more fecal samples may be required for detection. Morphologic examination is also an insensitive and subjective method. String test or biopsy can detect trophozoites, but these methods are invasive and uncomfortable for the patient. Therefore, the best means of detection is by identification of Giardia antigen or DNA in feces.

At Mayo, we strongly recommend the antigen detection method highlighted here with the red box. It is a highly sensitive and specific, non-invasive method that quickly provides an objective result. Of note, antibody testing is not very useful since Giardia trophozoites do not usually elicit a detectable antibody response.

Diagnosis of Giardiasis


Jump to section: