Individuals who are scheduled to undergo blood panel testing for celiac disease are not required to fast, according to Request A Test. However, they are advised to consume foods that contain gluten for approximately two weeks prior to testing, as gluten-free diets may affect the sensitivity of the tests.
Blood tests for celiac disease detect antibodies that suggest the presence of the condition but do not confirm it, according to the Celiac Disease Foundation. The TG-IgA antibody test measures the amount of tissue transglutaminase antibodies in the blood and is the most sensitive celiac test available. High levels of the antibodies are found in roughly 98 percent of individuals with the disease who eat a diet that contains gluten.