Allergy

Tissue Transglutaminase (tTG) Test — Screen for Coeliac Disease

Tissue transglutaminase antibodies are found in the blood of people with coeliac disease, an autoimmune condition triggered by gluten (a protein in wheat, rye, and barley). The anti-tTG test is considered the most sensitive and specific blood test for coeliac disease and is measured alongside total IgA to ensure accurate results. A positive result often leads to further investigation, including intestinal biopsy, for definitive diagnosis.

Why Test Transglutaminase?

This test is recommended if you have symptoms such as abdominal pain, diarrhoea, constipation, poor growth, weight loss, fatigue, or irritability. NICE guidelines recommend screening family members of coeliac patients, people with type 1 diabetes, autoimmune thyroid disease, IBS, unexplained iron, B12, and folate deficiencies, or persistent gastrointestinal symptoms.

What Do High Transglutaminase Levels Mean?

A positive or borderline result suggests that you may have coeliac disease and should visit a doctor to discuss further steps. Positive tests may be followed by an intestinal biopsy for definitive diagnosis. The presence of these antibodies can precede clinical symptoms by years.

What Do Low Transglutaminase Levels Mean?

A negative result means no antibodies to the marker were detected. However, a negative test cannot fully rule out coeliac disease or non-coeliac gluten sensitivity, as only one marker is tested. Follow-up with additional markers may be recommended.

Symptoms to Watch For

  • Abdominal pain and bloating
  • Chronic diarrhoea or constipation
  • Unexplained weight loss
  • Fatigue and irritability
  • Iron, B12, or folate deficiency
  • Mouth ulcers
  • Skin rash (dermatitis herpetiformis)
  • Joint pain

Who Should Get Tested?

  • People with gastrointestinal symptoms suggestive of coeliac disease
  • First-degree relatives of someone with coeliac disease
  • Individuals with type 1 diabetes or autoimmune thyroid disease
  • Those with unexplained nutrient deficiencies (iron, B12, folate)
  • People with IBS who want to rule out coeliac disease

How to Prepare for Your Test

You must eat a moderate amount of gluten every day for 2-3 weeks before taking this test for accurate results. Do not start a gluten-free diet before testing. Bring your ID to the sampling location. Bring valid ID to your appointment.

Order Your Blood Test

Test your Transglutaminase levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.

Celiac Disease Test →

Frequently Asked Questions

Is this the best blood test for coeliac disease?
Yes. Anti-tissue transglutaminase is considered the most sensitive and specific single blood test for coeliac disease. It is best used alongside total IgA to rule out IgA deficiency, which can produce false negative results.
Can I have coeliac disease with a negative test?
Yes, in rare cases. Some people with coeliac disease may test negative, especially if they have IgA deficiency or have already started a gluten-free diet. Additional markers like deamidated gliadin or Cyrex testing may be helpful.
What happens after a positive result?
A positive result should be discussed with a doctor, who may refer you for an intestinal biopsy to confirm the diagnosis. You should continue eating gluten until all tests are complete.
Do I need to eat gluten before the test?
Yes. Consume gluten daily for at least 2-3 weeks before testing. A gluten-free diet before the test can produce false negative results.
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Wellth Team

Wellth

Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.

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Medical Disclaimer

The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.