Sure, that would be difficult. Keeping wheat out of even dissimilar grains is currently a challenge for food producers and processors. The test would be the same, though, as testing any other grain for contamination, which is routine - test for gluten.
“Future potential treatments for patients with RCD include the development of genetically detoxified grains, oral and intranasal 'coeliac vaccines' to induce tolerance, inhibitors of TTG, and detoxification of immunogenic gliadin peptides via oral peptidase supplement therapy.”
As far as future treatments, this clinical review https://www.gponline.com/coeliac-disease-clinical-review/gi-... concludes that
“Future potential treatments for patients with RCD include the development of genetically detoxified grains, oral and intranasal 'coeliac vaccines' to induce tolerance, inhibitors of TTG, and detoxification of immunogenic gliadin peptides via oral peptidase supplement therapy.”