Forget the biopsy. You don't need to suffer that much.
Ask to your doc why he wants to perform a biopsy. If he suspects something, it might me fine. But if he is doing it because he doesn't know what else to do then it's just crazy.

I would look more about yeast, parasites or bacteria. You are at the right place on this forum. Try to find an holistic/environmental MD ASAP.

Please learn what Marjorie Crandall has to say about biopsy performed for no valid reason by reading her candida packet. You always have the right to ask questions and to say no to proposed treatment.

Check for parasites, bacteria, or yeast, do some liver flushes. Once you identified what the microorganism is, if it is not parasites, take kefir. For the diarrhea take 1-2 TBSP a day of psyllium and see if that helps.

I think that doing a biopsy at this point is premature and it may prove to not be necessary as Celiac experts say that Celiac Disease can be diganosed with a combination of lab tests and symptoms. Find out which tests for CD you had - they should have included alpha gliadin antibody levels, anti tissue transglutaminase antibody levels and endomysin levels. Both Metametrix Labs and Diagnos Tec Labs offer stool/fecal effect tests and will identify many harmful organisms, bacteria, yeasts and parasites and also test for some disease indicators - a celiac antibody is one and more sensitive than the blood tests.

Medical treatments for problem causing organisms in the gut work quite well for some people. Many of us use various self-treatment programs - some of them are described at the Liver Flush Support Forum . People with gluten sensitivity sometimes recover within several months after going gluten free. For more information of the variety of gluten sensitivities go to 'The Gluten Syndrome' website.