Celiac disease is a condition in which a person is not able to digest gluten, a protein found in wheat, barley & rye. Gluten is also present in other food products like soy sauce, salad dressings, vitamins & candies. If you suffer or have a family history of Celiac disease, your immune system reacts when you eat gluten. Symptoms include diarrhea, constipation, bloating, fatigue, weight loss & malabsorption. Children can show delayed growth. This test detects IgG type of tTG antibody to diagnose Celiac disease. This antibody is useful if your body does not show any IgA antibody response.