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Blood Test: Tissue Transglutaminase IgA, IgG

Reviewed by: Larissa Hirsch, MD
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What Is a Blood Test?

By taking and testing a small sample of a person’s blood, doctors can check for many kinds of diseases and conditions. Blood tests help doctors check how the body’s organs are working and see if medical treatments are helpful.

To help your child get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is anxious about it, work together on ways to stay calm.

What Is a Tissue Transglutaminase IgA (tTG-IgA) Test?

A tissue transglutaminase IgA (tTg-IgA) test is used to help doctors diagnose celiac disease. In this autoimmune disorder, the immune system mistakenly thinks that gluten — a protein in wheat, barley, rye, and oats — is a foreign invader. It makes antibodies that attack an enzyme in the intestines called tissue transglutaminase (tTG). Antibodies (also called immunoglobulins) are proteins that recognize and get rid of germs.

Why Are tTG-IgA Tests Done?

Doctors may order a tTG-IgA test if a child has symptoms of celiac disease, such as poor growth, belly pain, constipation, vomiting, diarrhea, or rashes.

The test also might be done if a child has a condition that makes celiac disease more likely (such as type 1 diabetes), thyroid disease, or a family member with celiac disease.

How Do We Prepare for a tTG-IgA Test?

For the test to be accurate, your child should be on a gluten-containing diet until the test is done.

What if I Have Questions?

If you have questions about the tTG-IgA test or what the test results mean, talk to your doctor.

Reviewed by: Larissa Hirsch, MD
Date reviewed: September 2021