My 18 month old had similar symptoms; beige and VERY acidic diarrhea. Sudden onset such that we thought it was a stomach virus, but it just never went away. Husband is celiac so we eliminated gluten and she started having normal stools again. We also did the blood test (altho not the complete panel) and it came back negative. With family history and response to diet, we went gluten-free and never looked back. There are good reasons to do the endo, though. Just wasn't for us. Maybe we'll let her decide to do that when she's older. If she can tolerate eating a gluten diet for that long, that is.