General
Tissue Transglutaminase Antibody (IgA)
Lab test

Tissue Transglutaminase Antibody (IgA)

The primary blood test used to screen for celiac disease. Ordered for people with GI symptoms, unexplained iron deficiency, or a family history of celiac disease. Must be consuming gluten regularly for at least 6 weeks before testing for accurate results. Results reviewed by a General Medicine clinician.

Receive actionable insights and deep analysis—not just lab values– in as little as 48 hours

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Most insurance accepted

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Available nationwide

What is a Tissue Transglutaminase Antibody (IgA) Test?

The tTG-IgA test measures IgA antibodies directed against tissue transglutaminase — the enzyme that becomes a target of the immune system when a person with celiac disease consumes gluten. It is the single most sensitive and specific blood marker for celiac disease and serves as the cornerstone of celiac screening in clinical practice.

Celiac disease screening

Elevated tTG-IgA is the primary blood-based indicator of celiac disease — reflecting the autoimmune response to gluten that causes progressive damage to the small intestinal lining. A positive result is strong evidence that further evaluation, including intestinal biopsy, is warranted.

Gluten exposure requirement for accuracy

tTG-IgA levels fall when gluten is removed from the diet — making it critical that patients consume a normal gluten-containing diet for at least 6 weeks before testing to avoid false negative results.

Treatment monitoring

After a confirmed celiac diagnosis and initiation of a gluten-free diet, declining tTG-IgA levels over time confirm that intestinal healing is occurring — providing objective evidence that dietary compliance is reducing the immune response.

Complete insights in as little as 48 hours

1

Book your test

Instantly schedule at 2,000+ labs nationwide, at a time that works for you. Most visits take 15 minutes or less, with both walk-ins and appointments available.

2

Get results in 48 hours

Your results are delivered quickly—and reviewed by medical professionals. You’ll get clear explanations, robust health insights, and recommended next steps tailored to your health needs.

3

Take action with physician guidance

Choose to review your results and manage your plan with a General Medicine physician—or simply use the insights on your own.

4

Track progress over time

Repeat annually to see trends, improvements, and new emerging risks or book individual tests that focus on your set goals

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Your care plan
Clinician

What's included

Test type

Blood sample

Collection method

Venipuncture

Fasting

Not required

Results processing time

1 to 2 days

tissue transglutaminase IgA antibody

Measures IgA antibodies against tissue transglutaminase (the main marker of celiac disease).

Virtual visit with clinician

Ongoing support, always available.

You’ll be supported by experienced clinicians who care for a wide range of health needs, from everyday concerns to more complex conditions.

Our clinicians track your progress over time and adjust your care as needed. If medication is prescribed, we’ll manage dosing and monitor for side effects. If lab testing is recommended, we review results and refine your plan accordingly. You’re never left to navigate care on your own.

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Frequently asked questions

What does the tTG-IgA test measure?

Tissue transglutaminase IgA (tTG-IgA) measures IgA antibodies against the enzyme tissue transglutaminase — the most sensitive and specific blood test for celiac disease. Elevated tTG-IgA strongly suggests an autoimmune reaction to gluten that is damaging the small intestinal lining.

Is this the same as the Celiac Disease Panel?

The tTG-IgA is the primary component of celiac testing. The Celiac Disease Panel includes this marker plus total IgA (to confirm you can produce IgA antibodies, which affects test validity). The standalone tTG-IgA may be ordered when the purpose is specifically to screen for celiac antibodies.

Do I need to be eating gluten for this test to be accurate?

Yes — this is critical. If you've already reduced or eliminated gluten, antibody levels will fall and the test may produce a false negative. You must be consuming a normal gluten-containing diet (at least 1–2 servings daily) for at least 6 weeks before testing.

What does a positive tTG-IgA mean?

A positive result is strong evidence of celiac disease, but definitive diagnosis still requires small intestinal biopsy to confirm villous atrophy. The positive test is the critical first step that guides whether endoscopy is warranted.

I have IgA deficiency — will this test work?

No — IgA-based tests produce false negatives in people with IgA deficiency. This is why total IgA is checked alongside tTG-IgA in the Celiac Disease Panel. If your IgA is low, IgG-based tests (DGP-IgG or tTG-IgG) are used instead.
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