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TTG
(a.k.a Tissue transglutaminase, IgA-anti-TTG, anti-TTG, coeliac screen)
minimum sample volume required ~ 5ml
Test Code: TTG
Tube type: SST
Special instructions
Patient must be on a gluten-containing diet for at least 6 weeks prior to testing.
Minimum repeat test interval
6 months (RCPath guidelines).
Reference range
<8
Units
AU/mL
Turnaround Time
3
days
Department: Biochemistry
Clinical Application
The IgA-anti-TTG assay is used to screen for coeliac disease and some other gluten-sensitive conditions (such as dermatitis herpetiformis).
An IgA-anti-TTG result of <0.2 AU/mL will be automatically tested for total IgA by the laboratory. If the total IgA result is <0.2 g/L, IgA-anti-TTG assay is unsuitable for use in diagnosis or monitoring of coeliac disease, the laboratory will automatically perform IgG-based coeliac serology.
Patients with positive IgA-anti-TTG results >8 AU/mL should be referred to paediatrics or adult gastroenterology as appropriate, and continue on a gluten-containing diet whilst awaiting a definitive diagnosis (often via biopsy). Where anti-IgA-TTG is >80 please also send a repeat sample for Endomysial Antibody testing.
Webpage updated: December 2025.
