sensitivity is a predecessor to celiac - by the time someone has celiac they may be very ill.
I use gliadin antibodies IgA and igg - simple blood test - 70% sensitivity - to see if patients are starting to react to wheat. Those numbers should be 1 or 2, if they are higher, go gluten-free 80-90% of the time. Near 20, get tested for celiac. Most people have amazing improvement in 1-2 weeks.