Ttg - TISSUE TRANSGLUTAMINASE (tTG) ANTIBODY, IgA

 
Note 1. To diagnose Celiac disease, the test should be performed before eliminating gluten from the diet
2. False positive results are seen in Type 1 Diabetes, Chronic Liver Disease, Heart Failure and Psoriatic or Rheumatoid Arthritis. It is likely that proteins other than tags may act as antigens for anti-tTG antibodies
3. False negative results may be seen in children below 2 years & patients with IgA deficiency. There Is high prevalence of IgA deficiency in Celiac disease thus simultaneous screening for IgA level has been recommended
4. A useful test for exclusion of Celiac disease is HLA - DNA testing for the presence of DQ2 (DQB1*02, DQA1*05) and DQ8 (DQB1*03, DQA1*03). Celiac disease can be excluded in 90% cases If all these alleles are negative
Comments:  This test is used for the determination of IgA autoantibodies to human tissue transglutaminase for the differential diagnosis of Celiac disease / Gluten sensitive enteropathy (GSE). Celiac disease is characterized by small intestinal damages with flat mucosa leading to malabsorption with depletion of key nutrients. Tissue transglutaminase is one of the main endomysial autoantigens that can be easily detected for the diagnosis of Celiac disease. Other recommended tests are Endomysial, Gliadin & Reticulin antibodies along with small intestinal biopsy. Negative serology does not exclude a diagnosis of GSE. IgA deficiency should be considered in patients with suggestive clinical presentation.