How will I know if I need to be tested for celiac or gluten intolerance?

Weight loss. If you are experiencing unexplained weight loss, gastrointestinal symptoms especially after having eaten gluten (usually in wheat), and even nerve problems (numbness, you should considered being tested for gluten intolerance. A simple blood test may provide the diagnosis (although not as definitive as an intestinal biospy) but you must be eating gluten for the test to be accurate.