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Testing for celiac disease: IgA Blood Test

Updated: Nov 8, 2022

Many community members were asking about their blood tests results. They wondered if the blood test results are accurate and some of them asked if it is normal to get blood tests after an endoscopy positive for celiac disease.

We need to clarify that there are two types of blood tests in celiac disease diagnosis: immunoglobulin and genetic. The blood tests asked in the community were concerning the immunoglobulin A (IgA) blood test, which is the most common first step in celiac disease diagnosis.

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Community questions about immunoglobulin blood test

The human body has many types of antibodies. One of the types of antibody in our blood is the IgA. There's a subgroup of the IgA antibodies associated with celiac disease, namely TTG-IGA. More specifically, the TG2-IgA antibodies (Husby and colleagues, 2019).


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Celiac disease diagnosis antibodies in blood

After compiling the data of 22 studies, Hill (2005) determined that the accuracy of TTG-IgA tests for correctly diagnosing people with celiac disease is between 77 and 100% of the times. This blood test is very helpful to diagnose celiac disease, particularly in children.


However, most of immunoglobulin blood tests are based on detecting IgA antibodies. Thereby, these tests may not allow to diagnose individuals who have both celiac disease and IgA deficiency.

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False negative rate of celiac disease blood test due to IgA deficiency

Before the blood test, you should continue eating gluten daily to make sure your body produces the antibodies that will later be detected in your blood sample.

Before the endoscopy, you should continue eating gluten daily to have evidence of an autoimmune attack in your intestines.

After being diagnosed with celiac disease, start your gluten-free diet and do not forget to have follow-up tests.

If symptoms continue in spite of a gluten-free diet and normal levels of TTG-IgA, a second endoscopy is advised to check the intestinal villi condition.

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Best practices before and after celiac disease diagnosis

Too much information, do not worry ! We summarized the main takeaways of this article for you.

If you have further questions related to celiac disease or other gluten-related condition, you can email them to us or leave the questions on the website chat. If your question can help more people with celiac disease, we will search scientific references and prepare content about it to share on our website.

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Main takeaways about celiac disease Ig blood tests

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