Test Background Coeliac disease is an autoimmune disorder of the small intestine that occurs in genetically-predisposed people of all ages from middle infancy. It is caused by a reaction to gliadin, a gluten protein found in wheat. Upon exposure to gliadin, the enzyme tissue transglutaminase modifies this protein and the immune system cross-reacts with the bowel tissue, causing an inflammatory reaction. Positive antibodies against tissue transglutaminase are highly specific and sensitive for the diagnosis of coeliac disease. These are of the IgA isotype, however IgA deficiency is common in this group of patients, and those that are IgA deficient should be tested for anti tTg IgG antibodies.
Clinical Indications Suspected gluten sensitivity (this test is specific for coeliac disease, but a jejunal biopsy is recommended for confirmation) Chronic diarrhea Failure to thrive and fatigue To monitor compliance with gluten-free diet
Reference Range <10 AU/mL
Sample Required RST (rust top)
Sample Volume 5-10 mL (1 mL serum)
Turnaround Time 7 days Additional Confirmatory tests: 14 days