Anti-Tissue Transglutaminase Immunoglobulin A (tTG IgA) Blood Test

Questions

• Do I need to keep eating gluten before this test?

  Yes. You need to be consuming gluten regularly for at least six weeks before the test. If you have already reduced or eliminated gluten, your antibody levels may be falsely low and the result unreliable.

• What does a positive tTG IgA result mean?

  It suggests your immune system is producing antibodies against tissue transglutaminase in response to gluten. This is strongly associated with coeliac disease, but a positive result should be followed up with a gastroenterologist for confirmatory testing.

• Can this test diagnose coeliac disease on its own?

  No. A positive blood test supports the suspicion of coeliac disease but is not sufficient on its own. Diagnosis is usually confirmed with an intestinal biopsy performed via endoscopy.

• What if I have IgA deficiency?

  IgA deficiency is relatively common and will cause a falsely low tTG IgA result. If IgA deficiency is suspected or known, your practitioner may order a DGP IgG test instead, which is not affected by IgA levels.

• Can I use this test to monitor my gluten-free diet?

  Yes. Once diagnosed with coeliac disease and following a gluten-free diet, tTG IgA levels should gradually fall. Rising levels may indicate inadvertent gluten exposure.

• Is coeliac disease the same as gluten intolerance?

  No. Coeliac disease is an autoimmune condition confirmed by specific antibodies and intestinal damage. Non-coeliac gluten sensitivity is a separate condition that does not produce the same antibodies or cause the same type of gut damage.