In 1994 I was diagnosed with celiac disease, which led me to create Celiac.com in 1995. I created this site for a single purpose: To help as many people as possible with celiac disease get diagnosed so they can begin to live happy, healthy gluten-free lives. Celiac.com was the first site on the Internet dedicated solely to celiac disease. In 1998 I founded The Gluten-Free Mall, Your Special Diet Superstore!, and I am the co-author of the book Cereal Killers, and founder and publisher of Journal of Gluten Sensitivity.
This is not Medical advice: The biopsy determination of celiac disease requires demonstration of the abnormalities in the proximal small intestine. It is not possible to get such a biopsy going through the anus. The colonoscope does not reach that far. The biopsy instrument must go through the mouth. This is usually achieved with a upper endoscopy (AKA gastroscopy, EGD) A colonoscopy is frequently preformed for the investigation of diarrhea but does not and can not detect celiac disease. Joseph A. Murray, MD.