A rarely performed diagnostic procedure in which a tissue sample from the jejunum (the part of the small intestine between the duodenum and ileum) is removed for analysis through a tube that enters the body orally. A jejunal biopsy is performed when an individual experiences symptom such as malabsorption (impaired absorption of nutrients through the small intestine), diarrhea, and weight loss. Eating and drinking are stopped for at least 8 hours before the procedure. To reduce discomfort, the throat is sprayed with a local anesthetic immediately before the procedure. A tube is inserted in the mouth and through the stomach into the small intestine.
Removal of a piece of the lining (mucosa) of the upper small intestine. This can be done by a surgical operation but is usually performed by a special metal capsule, swallowed by the patient. When the capsule is in the jejunum a small knife within it is triggered by suction on an attached tube, cutting off a small piece of mucosa. The specimen may be examined microscopically to assist the diagnosis of celiac disease or intestinal infections, or its enzyme content may be measured chemically to detect, for example, ‘lactase deficiency.