From White Labs:
"In addition to eliminating chill haze, Clarity-Ferm significantly reduces the gluten content in beers made with barley and wheat. A Clarity-Ferm treated beer made from barley or wheat usually tests below 10 ppm of gluten, the current international standard for gluten free. White Labs offers gluten testing for beers, this test will allow brewers to know the gluten level of the beers it produces, but brewers are not allowed to use this value on their labels until the FDA completes its validation.
The TTB has issued interim labeling guidelines for beers made with gluten containing grains, and it states:
"TTB will allow use of the statement 'Processed or Treated or Crafted to remove gluten,' together with a qualifying statement to inform consumers that: (1) the product was made from a grain that contains gluten; (2) there is currently no valid test to verify the gluten content of fermented products; and (3) the finished product may contain gluten."