Blood tests to look for specific antibodies (anti-gliadin, anti-endomysial and anti-tissue transglutaminase) are used to diagnose celiac disease. One or more of these antibodies are found in almost everyone with celiac disease. They rarely are found in people who do not have this disease.
If your doctor suspects celiac disease, he or she may recommend a biopsy of the intestine. A biopsy requires the procedure known as endoscopy (EGD or "esophagogastroduodenoscopy"), which allows your doctor to remove a tiny piece of tissue that can be examined under a microscope. Under a microscope, the biopsy sample can reveal damage to the tiny villi, which will appear flatter than usual. Inflammatory cells can also be seen on a microscope examination of a biopsy.