<<Disclaimer: Verify this information before applying it to your situation.>> Thanks so much for all of your replies, it is so nice to hear from so many folks with experience! Some folks thought that a diagnosis was worth it. Some thought it wasn't if he does so much better on a GF diet, why make him go through that? The concensus was that at LEAST 6 wks is necessary for a gluten challenge, but that even then it might not show positive. Lots of folks replied explaining the difference between allergies and celiac to me. And that a prick test will not show celiac. I guess I did a really bad job explaining myself. I was hoping that he had an allergy, but when it didnt show up on the prick test, that what convinced me that he probably has CD. Because I know that CD doesn't show up, but that he still reacts so stongly, that is why I ask if I still needed to challenge him and get a biopsy or blood test diagnosis, or if that in itself was a good enough "test". Also, is there any other reason why he would react to wheat so strongly and not have a histamine reaction - other than Celiac?? I have biopsy diagnosed celiac. He does have various other allergies and intolerances, most of which I hope will clear up when his system is totally clear of gluten (turns out that the cereal does use a barley derived malt). He hasn't pooped in a full day since I took him off of it (which is a miracle for this ki Here is one more question: What is the difference between a gluten intolerance and celiac? Is there one? Thanks, Emily *Support summarization of posts, reply to the SENDER not the CELIAC List*