Understanding Tissue Transglutaminase IgA: Normal vs Optimal Ranges

?What is Tissue Transglutaminase IgA?

Tissue transglutaminase IgA (tTG-IgA) is the primary diagnostic test for coeliac disease. Transglutaminase 2 (tTG2) is an intestinal enzyme that deamidates gliadin peptides from wheat gluten; in genetically susceptible individuals (HLA-DQ2/DQ8), this triggers a T-cell response and IgA antibody production against both gliadin and tTG2 itself. With sensitivity of 95–98% and specificity of 95%, tTG-IgA is the most reliable single coeliac screening test.

!Why It Matters

Undiagnosed coeliac disease causes progressive villous atrophy in the small intestine, leading to malabsorption of iron, calcium, vitamins D and B12, and folate. Longstanding untreated coeliac disease significantly increases the risk of osteoporosis, infertility, peripheral neuropathy, and small bowel lymphoma. A strict gluten-free diet normalises tTG-IgA and allows intestinal healing.

Reference Ranges

Lab normal ranges may vary between laboratories. Optimal and longevity targets are based on research literature and should be interpreted with your physician.

Symptoms of Imbalance

• Chronic diarrhoea, steatorrhoea (fatty stools), and weight loss
• Abdominal bloating and cramping after wheat consumption
• Unexplained iron-deficiency or megaloblastic anaemia
• Dermatitis herpetiformis: itchy blistering rash on elbows and knees
• Fatigue, bone pain, and neurological symptoms (ataxia, neuropathy)

How to Improve Your Levels

• 1Strict, lifelong gluten-free diet is the only effective treatment for coeliac disease
• 2Work with a specialised dietitian to eliminate cross-contamination risks
• 3Supplement nutritional deficiencies: iron, calcium, vitamins D and B12, folate
• 4Monitor tTG-IgA every 6–12 months on gluten-free diet until normalisation
• 5Screen first-degree relatives — risk is 1 in 10 with coeliac family member

When to Test

Primary coeliac disease screening; unexplained iron deficiency; dermatitis herpetiformis; metabolic bone disease; family history of coeliac; type 1 diabetes or thyroid disease (higher coeliac risk).

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