infections
Giardiasis
Diagnosis of Giardiasis
Stool tests The symptoms often suggest giardiasis. The easiest way to make the diagnosis of giardiasis is by testing the stool for proteins (antigens) released byGiardia lambliaor for its DNA. Microscopic examination of stool samples may also detect the parasite. However, because people who have been infected for a long time tend to excrete the parasites at unpredictable intervals, repeated microscopic examinations of stool are often needed. If these tests do not identify what is causing the intestinal symptoms, doctors may use a flexible viewing tube ( Endoscopy ) to examine the upper part of digestive tract, including the first part of the small intestine (duodenum). Doctors may use this procedure to obtain a sample of the contents of the small intestine for examination. 