A biopsy is a medical test in which cells or tissues are removed from the body. Usually, the cells or tissues (known as the biopsy sample) are examined under a microscope by a pathologist. Sometimes, the biopsy sample is also analyzed chemically.
In the biopsy that is done to confirm the diagnosis of celiac disease, small amounts of tissue are removed from the small intestine during a procedure known as an endoscopy.
Sometimes, the biopsy sample is also sent to a laboratory for culture and sensitivity testing, or analyzed chemically.