Tissue Transglutaminase (tTG), IgA

Additional Information:

UFHPL Epic order code: LAB723

Studies have demonstrated that IgA endomysial antibody tests have >99% specificity for gluten-sensitive enteropathy.1 Recently, the endomysial antigen has been identified as the protein cross-linking enzyme known as tissue transglutaminase (tTG).2


  1. Volta U, Molinaro N, De Franchis R, et al. Correlation between IgA antiendomysial antibodies and subtotal villous atrophy in dermatitis herpetiformis. J Clin Gastroenterol. 1992 Jun; 14(4):298-301. PubMed 1607605
  2. Dieterich W, Ehnis T, Bauer M, et al. Identification of tissue transglutaminase as the autoantigen of celiac disease. Nat Med. 1997 Jul; 3(7):797-801. PubMed 9212111

CPT Code(s):


Specimen Requirements:

Important: Specimens should be free of bacterial contamination, hemolysis and lipemia.

Type: Serum

Container/Tube: Red-top tube or gel-barrier tube

Sample Volume: 1 mL

Minimum Volume: 0.3 mL (Repeat testing is not possible with this specimen volume.)

Storage: Refrigerate specimens after collection.

Stability (collection to time of analysis/testing):

  • Ambient: 14 days
  • Refrigerated: 14 days
  • Frozen: 14 days
  • Freeze/Thaw cycles: Stable (x3)
Rejection Criteria:

  • Gross bacterial contamination
  • Lipemia
  • Hemolysis


This test is used to detect antibodies to aid in the diagnosis of gluten-sensitive enteropathy (GSE), such as celiac disease and dermatitis herpetiformis.


A negative tTG IgA result in an untreated patient does not rule out gluten-sensitive enteropathy. This result can often be explained by selective IgA deficiency, a relatively frequent finding in celiac disease. Results of this assay should be used in conjunction with clinical findings and other serological tests.


Enzyme immunoassay (EIA)

Reference Values:

Reference Intervals

  • Negative: 0 – 3 units/mL
  • Weak-positive: 4 − 10 units/mL
  • Positive: > 10 units/mL