Blood tests, such as the tissue transglutaminase test (tTG) or the antiendomysial (EMA) antibody test, measure the autoimmune response triggered by gluten that occurs at that particular point in time. These are important tests because they characterize the extent to which the immune system is responding to gluten. Unlike antibody testing, the HLA genetic test measures the presence or absence of genetically programmed molecules found on the surface of some cells. The HLA gene test for celiac disease can be performed at any time after birth (and even in the cord blood at birth)—an individual is either born with or without these factors and they do not change over time. July, 2012