My personal experience with gluten intolerance testing:
I started glutenintollerancetest.com because I have gluten intolerance, which went undiagnosed for most of my life.
On the one hand I was always in good shape and strong. I played sports in high school and worked as a wildland fire fighter, which involved a lot of physical training.
On the other hand I always felt tired, got sick very easily and everything I did seemed to take much more effort than it should. After years of feeling this way, I was sort of resigned to it. I felt something was wrong, but I lacked a frame of reference and wasn’t really sure. My attitude was: “it is what it is, just suck it up.”
It wasn’t untill I was about 30 that I finally took a gluten intolerance test, which revealed somewhat high levels of anti-gliadin. My sIGA levels, however, were also extremely low. This means that my body produces very little antibodies. And a large percentage of the few antibodies I did produce, went to fighting Gliadin.