Human intestinal parasites are diagnosed through a number of ways including a stool sample, endoscopy or colonoscopy, blood tests and imaging tests such as an MRI, states the Centers for Disease Control and Prevention. The type of test that is used depends on the patient's symptoms.
A stool test is done when a patient has intestinal cramping, diarrhea or gas, explains the Centers for Disease Control and Prevention. The samples are usually collected over several days then examined for the presence of eggs or parasites. Endoscopy or colonoscopy is used when a stool sample doesn't offer a diagnosis. In this case, a tube with a camera is placed in the intestines for a close look.
Some intestinal parasites are diagnosed through a blood test, according to the Centers for Disease Control and Prevention. These tests look for signs of parasitic infection in the blood. There are two main types of blood tests. A serology test looks for antibodies or antigens to diagnose a parasite. A blood smear looks for signs of parasites in the blood. If there are parasites that are causing lesions on the organs of the body, an X-ray, magnetic resonance imaging scan or computerized axial tomography scan may be used to positively diagnose that parasites are present.