Routine endoscopy only looks at a small portion of the small intestine. There are other methods to look directly at all of the small intestine.

One method has been the capsule endoscopy first described in 2000. http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum

Another method, developed in Japan and first described in 2005, is the double balloon enteroscopy. http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_DocSum

Double balloon enteroscopy apparently can pick up lesions missed by capsule endoscopy. One advantage of the double balloon over the capsule is that areas can be treated or biopsied with the double balloon. Both of these procedures may be helpful for people with celiac disease who do not respond to a GF lifestyle.
http://www.ncbi.nlm.nih.gov/entrez/q...=pubmed_docsum
Anne