"We only embrace tests that have endured rigorous scientific evaluations. So far, these tests have received no evidence-based support."
"There is not yet reliable data about cross-reactivity. As for the alleged possibility that many gluten-free foods or drinks (such as coffee, milk, orange juice, etc.) would trigger symptoms in celiac individuals due to hidden antigens mimicking gluten or cross-reacting with anti-gluten antibodies, it must be clearly stated that this is all false information, devoid of any scientific basis, and must be rejected as untrue."
I understand what you are saying and this is a controversial subject. The theory makes sense, however, and understanding it has helped me significantly. And it is important to note that not everyone with celiac reacts to foods other than the standard gluten ones. We probably see a higher percentage here because you have to be pretty desperate to spend a lot of time on a disease forum looking for answers.
Personally, I'm not interested in going the Cryex or Eurolab route and I have no idea how accurate the tests are. I don't need a lab test to tell me that my forbidden list includes corn, soy, rice and nightshades. And I certainly don't need to spend a small fortune to know that I have yet to find a 'gluten free' product on the shelf that didn't make me sick.
Anyway, beyond the accuracy of lab tests, the following info might prove useful for some. I still prefer the way it is explained by the link provided above.