My son has been losing weight pretty fast. Ten lbs in a week. His bloodwork was normal and he was even tested for Mono to rule that out. He is nauseous and vomits all of the time. He has no appetite and feels full and says it feels as if he has vomit in his throat. He is taking Nexium and Zantac, they are helping a little but not enough. Dr wants to have him have an upper GI scope. How do you test for Celiac? A friend said she thinks that this could be what he is dealing with and I would rather rule it out before he has a scope done. Just need a direction to try. Any ideas???