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→Diagnosis
===Laboratory Tests===
===Laboratory Tests===
[[Image:Giardiasis duodenum high power.jpg|thumb|right|150px|Giardia trophozoites in the duodenum. Source: Wikimedia Commons; Author: Nephron (2009)]]
Diagnosis is confirmed by demonstrating ''[[Giardia]]'' antigen, trophozoites or cysts in the faeces. The simplest method is to examine fresh faecal smears for cysts (and occasional trophozoites), but sensitivity is improved by using concentration techniques. Centrifugal flotation in zinc sulphate solution or sugar flotation solution are both appropriate, but zinc sulphate solution is preferred as it causes minimal distoryion to cysts. In this technique, faecal material is centrifuged and saturated with zinc sulphate mixture before the fluid from the top of the tube is placed on a microscope slide. Diff-Quik or Lugol's iodine are used to stain cysts and trophozoites, a coverslip is applied, and the slide is examined under the microscope. Although infrequently detected, ''[[Giardia]]'' trophozoites are approximately 8 x 15 micron tear-drop shaped organisms which contain two nuclei. They can sometimes be seen to move in a "falling leaf" pattern. Cysts are around 12 microns long and, if not distorted, oval in shape. When looking for cysts, three samples collected at two to three day intervals should be examined as shedding is intermittent.
Diagnosis is confirmed by demonstrating ''[[Giardia]]'' antigen, trophozoites or cysts in the faeces. The simplest method is to examine fresh faecal smears for cysts (and occasional trophozoites), but sensitivity is improved by using concentration techniques. Centrifugal flotation in zinc sulphate solution or sugar flotation solution are both appropriate, but zinc sulphate solution is preferred as it causes minimal distoryion to cysts. In this technique, faecal material is centrifuged and saturated with zinc sulphate mixture before the fluid from the top of the tube is placed on a microscope slide. Diff-Quik or Lugol's iodine are used to stain cysts and trophozoites, a coverslip is applied, and the slide is examined under the microscope. Although infrequently detected, ''[[Giardia]]'' trophozoites are approximately 8 x 15 micron tear-drop shaped organisms which contain two nuclei. They can sometimes be seen to move in a "falling leaf" pattern. Cysts are around 12 microns long and, if not distorted, oval in shape. When looking for cysts, three samples collected at two to three day intervals should be examined as shedding is intermittent.
===Endoscopy===
===Endoscopy===
The above tests may also be performed using duodenal aspirates obtained by endoscopy.
The above tests may also be performed using duodenal aspirates obtained by endoscopy.
===Pathology===
===Pathology===
Gross lesions are not normally found at post-mortem examination.
Gross lesions are not normally found at post-mortem examination. Giardia trophozoites may be seen in the lumen following intestinal biopsy.
==Treatment==
==Treatment==