Coeliac Disease Blood Test (tTG-IgA)
A blood test that looks for antibodies seen in coeliac disease.
Quick Summary
To screen for coeliac disease in people with symptoms or risk factors.
Tissue transglutaminase IgA (tTG-IgA) and total IgA.
Keep eating gluten until the test, or it may be falsely negative.
Overview
A positive test is usually confirmed with an endoscopy and biopsy.
Total IgA is checked because IgA deficiency gives false negatives.
What It Measures
tTG-IgA
Coeliac antibodies.
Total IgA
To check the test is valid.
How It's Performed
- 01
Preparation
Usually no special preparation. Tell the staff about medicines you take.
- 02
Blood sample
A small amount of blood is taken from a vein in your arm with a thin needle.
- 03
Afterwards
Press on the spot for a minute. A small bruise is common; you can go back to normal activities.
Interpreting Results & Next Steps
Discuss with Doctor
Normal ranges differ between laboratories, ages and sexes; always use the range printed on your report and ask your doctor what your results mean.
If values are High:
A raised tTG-IgA suggests coeliac disease.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.
- Celiac Disease Screening(opens in a new tab) · MedlinePlus, US National Library of Medicine