How do you get testing for food intolerance like lactose and gluten?

Simple testing. Lactose intolerance can be objectively assessed by breath testing or subjectively by response to lactase replacement or lactose avoidance/then reintroduction. Serum testing to tissue transglutaminase antibody and/or anti-endomysial antibody are sensitive markers for gluten sensitive enteropathy. These markers can also assess a celiac patient's compliance with gluten avoidance.