Tissue Transglutaminase IgG
Label Mnemonic: TTGG
Epic Lab Code: LAB8014
Downtime Form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
6240 RCP
Collection Medium:
Plasma Separator Tube 4.5 mL
Adult - 3 mL plasma separator tube
Pediatric - two Microtainer® devices
Testing Schedule:
24 hrs/day, 7 days a week, including holidays.
Turn Around Time:
3 hours (upon receipt in laboratory)
Reference Range:
Negative: <15 U/mL
Positive: 15 U/mL or greater

This testing is not directly orderable and is only available as reflex to tissue transglutaminase IgA if total IgA is too low for tissue transglutaminase IgA measurement.
Celiac disease or gluten-sensitive enteropathy is an immune- mediated disorder that primarily affects the gastrointestinal tract and is characterized by chronic inflammation of the small intestine mucosa, which may result in atrophy of intestinal villi, malabsorption and a variety of clinical manifestations. It is caused by a pathological intolerance to gliadin, the alcohol-soluble fraction of gluten in wheat, rye and barley. Celiac disease manifests at any age with a peak onset in early childhood. Recent studies now suggest that its prevalence is in the range of 0.5 to 1.0% of the U.S. population with certain populations having an increased prevalence of celiac disease. Celiac disease is also associated with selective IgA deficiency and autoimmune disorders. The US incidence rate is 1:130, which is similar to European countries. Diagnosis of celiac disease is based on a combination of clinical symptoms and the following factors: IgA and/or IgG antibodies to tissue transglutaminase (TTG) IgA and/or IgG antibodies to deamidated gliadin Endomysial IgA and/or IgG antibodies Human leukocyte antigen (HLA)-DQ2 or DQ8 genotypes Biopsy of the small intestine (demonstrating flat mucosa) Or a patient's satisfactory response to a gluten-free diet (GFD). IgA deficiency is more common in the celiac disease (2-3%) versus the average population (0.1-0.2%). Therefore, it is recommended that IgG antibodies to deamidated gliadin be determined if there is total IgA deficiency. TTG IgG has much lower sensitivity (44%) than TTG IgA in patients without IgA deficiency. Therefore, it is not recommended to test TTG IgG except when there is IgA deficiency. References: 1. The National Institutes of Health (NIH) Consensus Development Conference on Celiac Disease, NIH Consensus Development Conference Statement, June 28-30, 2004. 2. van der Windt, et al. Diagnostic Testing for Celiac Disease Among Patients with Abdominal Symptoms: a Systematic Review. JAMA May 2010, 303(17);1738-46. 3. G. Holmes, C. Catassi, A. Fasano. Fast Facts: Celiac Disease. 2nd Edition; August 2009, 57-63. 4. Rashtak S., Ettore M., Homberger H., Murray J. Comparative Usefulness of Deamidated Gliadin Antibodies in the Diagnosis of Celiac Disease. Clin Gastroenterol Hepatol April 2008, 6(4); 426- 32. 5. Green, P.H., Jones. R. Celiac Disease: A Hidden Epidemic. 2006, 45-48. 6. Van Meensel B, Hiele M, Hoffman I, et al. 2004. Diagnostic accuracy of ten second-generation (human) tissue transgluta¬minase antibody assays in celiac disease. Clin Chem. 50: 2125–35.
Multiplex flow immunoassay
CPT Code: