Tissue Transglutaminase IgG
This blood test measures tissue transglutaminase IgG antibodies linked to coeliac disease. It is particularly useful when IgA-based testing is unreliable or inconclusive.
Turnaround time
Results available 5 days after arrival in lab. Doctor's report sent the day after results available (if required)
Biomarkers count
1
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Details about Tissue Transglutaminase IgG
What is the Tissue Transglutaminase IgG test?
The Tissue Transglutaminase IgG (tTG IgG) test measures IgG antibodies directed against tissue transglutaminase, an enzyme involved in maintaining the lining of the small intestine. In coeliac disease, exposure to gluten triggers an autoimmune response that damages intestinal tissue and leads to antibody production.
Unlike the tTG IgA test, this IgG-based test does not rely on normal IgA levels. It is therefore especially useful in individuals with IgA deficiency, where standard coeliac screening tests may give false-negative results.
This test is used as an alternative or complementary investigation when coeliac disease is suspected.
Why do I need a Tissue Transglutaminase IgG test?
Some people with coeliac disease cannot be reliably assessed using IgA-based tests due to IgA deficiency or atypical immune responses. In these cases, IgG antibodies provide important diagnostic insight.
You may need this test if you:
- Have symptoms suggestive of coeliac disease
- Have known or suspected IgA deficiency
- Have negative tTG IgA results but ongoing symptoms
- Experience chronic digestive issues or bloating
- Have unexplained fatigue or nutritional deficiencies
- Have iron deficiency or anaemia
- Have a family history of coeliac disease
- Have other autoimmune conditions
Testing helps avoid missed diagnoses when standard screening is insufficient.
Benefits of the test
- Alternative coeliac screening option
Useful when IgA-based testing is unreliable. - Suitable for IgA deficiency
Detects immune response independent of IgA levels. - Supports diagnosis in complex cases
Helps clarify unclear or conflicting results. - Detects autoimmune intestinal activity
Identifies gluten-related immune response. - Simple blood-based testing
Requires only a single blood sample. - Useful alongside other coeliac markers
Complements tTG IgA and total IgA testing. - Supports early identification
Helps reduce delayed diagnosis. - Applicable across age groups
Used in adults and children when indicated.
Step-by-step: How we offer testing
Clinic-based testing (UK-wide)
- Choose your nearest UK clinic
- Attend your appointment
- A clinician draws a blood sample
- Sample is sent to the laboratory
- Results are issued once analysis is complete
Home or hotel visit (+£60, UK-wide)
- Book a mobile phlebotomist
- Blood sample taken at your home or hotel
- No need to attend a clinic
- Sample securely transported to the laboratory
Your results explained
Negative (unlikely coeliac disease)
- tTG IgG within reference range
- UK standard (typical): <7 U/mL
- Suggests no evidence of IgG-mediated coeliac autoimmunity
Borderline result
- Slightly raised antibody levels
- UK standard: 7–10 U/mL
- May reflect early disease or non-specific immune response
Positive (suggestive of coeliac disease)
- Elevated tTG IgG antibodies
- UK standard: >10 U/mL
- Supports diagnosis of coeliac disease, especially with compatible symptoms
Results should be interpreted alongside clinical findings and other coeliac-related tests.
How It Works
Simple steps to get your results
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Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
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WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.