The clipper can be used to remove a small piece of the bowel lining during the procedure. This is called a biopsy. You will not feel any discomfort.The whole procedure takes about 10 minutes. The biopsy specimen will be sent to the laboratory to examine the size and shape of the villi. This will confirm diagnosis.It is usual to repeat this test after several months on a gluten-free diet, to check that the lining has recovered.