Lab marker · High

High Tissue transglutaminase IgA antibody (anti-tTG): what it means

A Tissue transglutaminase IgA antibody (anti-tTG) result above the normal range is considered high. Here is what a raised Tissue transglutaminase IgA antibody (anti-tTG) can point to, and when it is worth discussing with a doctor.

Reference range: negative <7 U/mL; a positive test with symptoms suggests coeliac disease — must always be read with total IgA

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What a high Tissue transglutaminase IgA antibody (anti-tTG) can mean

  • Coeliac disease — the main reason for a positive result, especially with symptoms; needs confirming with a small-bowel biopsy.
  • A high level (several times the upper limit) — makes coeliac disease very likely and, in some pathways, may allow diagnosis without biopsy.
  • Ongoing gluten exposure in known coeliac disease — a persistently positive level suggests the gluten-free diet is not being fully followed.
  • Occasionally other autoimmune conditions or liver disease — a weakly positive result can be non-specific.

When to discuss with a doctor

Anti-tTG IgA is the first-line test when coeliac disease is suspected — for example with long-standing diarrhoea, bloating, unexplained iron, folate or vitamin-D deficiency, weight loss, or a family history. Two points are essential for a valid result: keep eating gluten until the test (and any biopsy) is done, and have a total IgA checked at the same time so an IgA deficiency does not hide a true positive. A positive result normally leads to a confirming biopsy of the small intestine rather than starting a gluten-free diet straight away, because the diet must not be started before the diagnosis is secured. Mediora.AI surfaces a positive anti-tTG alongside the deficiencies coeliac disease causes (iron, folate, vitamin D) so the pattern is visible, but the diagnosis and next steps belong with your doctor.

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Mediora.AI is informational - interpretation, not a diagnosis. A single out-of-range value is common and often benign; always discuss decisions with your doctor.