The author of this article left out some very important information. Coffee is but one of several foods that can cross react with gluten. The list from Cyrex Labs (I removed things that are fractionated foods) includes some gluten-containing foods but also contains some that we've come to view as healthful. Perhaps testing for those with gluten sensitivity is a very good idea.
Cow's Milk IgG, IgA
American Cheese IgG, IgA
Chocolate IgG, IgA
Sesame IgG, IgA
Hemp IgG, IgA
Rye IgG, IgA
Barley IgG, IgA
Polish Wheat IgG, IgA
Buckwheat IgG, IgA
Egg
Soy
Sorghum IgG, IgA
Millet IgG, IgA
Spelt IgG, IgA
Amaranth IgG, IgA
Quinoa IgG, IgA
Yeast IgG, IgA
Tapicoca IgG, IgA
Teff IgG, IgA
Oats IgG, IgA
Coffee IgG, IgA
Corn IgG, IgA
Rice IgG, IgA
Potato IgG, IgA
Whey