Giardiasis can be diagnosed by checking a person’s stools (faeces) for giardia cysts.
A stool sample is usually sent to the microbiology laboratory in your nearest hospital to be tested.
Up to three stool samples may need to be taken over a number of days as giardia cysts aren't always passed out of the body each time you go to the toilet. If someone has typical symptoms of giardiasis, and the first sample tests negative, further samples may need to be tested in order to be certain.
Further testing
If repeated stool samples are negative but symptoms, such as bloating or pain continue, an endoscopy (telescopic examination of the intestines) may be recommended. Samples taken during the endoscopy may show the giardia parasite.
A more advanced test is available in some laboratories across the UK. It checks for specific antigens in your stools. However, this type of test is usually used only to test a large number of people over a short period of time, such as during a suspected giardiasis outbreak.
