Tests for Giardiasis
Giardiasis is a condition caused by infection by a microscopic parasite called Giardia lamblia. The illness occurs worldwide and can spread by food, from person to person and in water. Symptoms of giardiasis include cramps, bloating, nausea, vomiting, low-grade fever and diarrhea. Giardiasis often clears up without treatment, but it is important to confirm that the infection is giardiasis and not something more serious.
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Stool Sample
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Your doctor will likely want to collect at least one and perhaps several stool samples. There are a few ways to do this. You may catch the stool on plastic wrap placed over the toilet or use a kit with special toilet paper. Place the samples in a clean container and return them to your health care provider or the laboratory. For a child in diapers, position plastic wrap in the diaper in such a way as to exclude urine from the stool. Again, place the sample in a clean container and return it. At the laboratory technicians check a small sample of the stool under a microscope. This reveals the presence of parasites or parasite eggs.
Enteroscopy
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This test examines the small bowel. A very narrow, flexible tube is inserted through the mouth or nose. Maneuvering down, the doctor is able to remove a sample of tissue. This tissue is then examined for evidence of giardiasis.
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String Test
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In this test, the patient swallows a weighted gelatin capsule attached to a string. Four hours later the capsule is pulled back out of the mouth with the string. Any material attached to the capsule is examined for the presence of parasites. A doctor orders this test only when she or he suspects a parasitic infection but has found no evidence in the stool. It is rarely performed in the United States.
What to Expect
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Providing a stool sample, while perhaps an unpleasant task, is not difficult or painful. An enteroscopy can be somewhat uncomfortable, though you will receive a numbing medication and possibly a light sedative. When the biopsy is removed, you may feel slight cramping. You may have trouble swallowing the capsule in a string test, and may feel like vomiting when it is pulled back out. However, it should not be overly painful.
Results
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Any samples obtained should indicate the presence of the Giardia lamblia parasite or its eggs. If so, the doctor may choose to allow you to fight the infection naturally or provide you with antibiotics such as metronidazole or tinidazole.
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