Yes, very helpful, thanks! So, in theory (of course) would you think if she were taking Zyrtec (and prevacid, FWIW) at the time of the scope, could her MAST cells be masked or less? I know for RAST testing and skin testing you must be off of your anti-histamine, but for this would it matter? Gracie's been on daily Zyrtec since she turned 2. Hmmm....