Celiac Disease Blood Test Results Explained: What They Mean
Also known as: celiac disease test, celiac blood test results, tTG-IgA
Celiac disease blood tests screen for antibodies your immune system makes when you eat gluten. The main test is tTG-IgA (tissue transglutaminase antibody); a positive result suggests celiac disease and usually leads to a confirming intestinal biopsy, while a negative result makes it unlikely — but only if you were eating gluten before the test.
How blood tests are used
Blood tests are the first step in screening for celiac disease, but they don't diagnose it alone. Because the antibodies only appear when gluten is in your diet, you must be eating gluten for the tests to be accurate. A positive antibody result is typically confirmed with an endoscopy and small-intestine biopsy.
Key celiac blood tests
| Test | What it checks |
|---|---|
| tTG-IgA | The primary screening test; measures tissue transglutaminase antibodies. Most sensitive single test. |
| Total IgA | Checked alongside tTG-IgA to rule out IgA deficiency, which can cause a false negative. |
| EMA-IgA | Endomysial antibody; highly specific, often used to confirm a positive tTG-IgA. |
| DGP (IgA/IgG) | Deamidated gliadin peptide antibodies; useful in young children or IgA-deficient patients. |
What celiac results mean
- Positive tTG-IgA (especially high titer) strongly suggests celiac disease and warrants biopsy confirmation.
- Negative tTG-IgA with normal total IgA makes celiac disease unlikely — if you were eating gluten.
- A positive test with low total IgA can be a false negative; DGP or IgG-based tests are used instead.
- Weakly positive results may need repeat testing or specialist referral.
Understand your own results
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Frequently asked questions
Can I have celiac disease with a negative blood test?
It's possible but uncommon. A negative tTG-IgA usually makes celiac unlikely, but false negatives occur if you weren't eating gluten before the test or if you have IgA deficiency. If suspicion is high, doctors check total IgA, use IgG-based tests, or proceed to biopsy.
Do I need to eat gluten before a celiac test?
Yes. Celiac blood tests detect antibodies that only form in response to gluten. If you've already cut gluten out, the tests can be falsely negative. Guidelines generally recommend eating gluten daily for several weeks before testing — do this under medical guidance.
Does a positive celiac blood test confirm the diagnosis?
Not by itself. A positive antibody test is a strong signal, but the standard next step for adults is an endoscopy with a small-intestine biopsy to confirm celiac disease before starting a lifelong gluten-free diet.
Related biomarkers
Medically reviewed by Antonieta Rueda, MD and Ayham Shneker, MD · Last reviewed July 6, 2026
This article is for informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Blood tests are interpreted by a clinician alongside your symptoms and history. Always consult your healthcare provider about your results.