tTG-IgA · high result
What does a high tTG-IgA mean?
Short answer
A high tissue transglutaminase IgA (tTG-IgA) is the strongest blood signal for celiac disease — above ten times the upper limit it is almost always celiac. Mild elevations also occur with type 1 diabetes, autoimmune thyroid or liver disease and other autoimmune conditions. The result is only meaningful if total IgA is normal and you were eating gluten before the draw; confirmation is by endomysial antibody and, usually, small-bowel biopsy while still on gluten.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
What is the normal range for tTG-IgA?
- age 18+: 0.000 – 4.00 U/mL
Strongly suggests celiac disease, especially when paired with symptoms or genetic risk. Confirmed by biopsy.
Full reference table, citations and testing options: tTG-IgA biomarker page.
What are the common causes of high tTG-IgA?
- Celiac disease (the higher, the more specific)
- Type 1 diabetes, autoimmune thyroid disease, autoimmune hepatitis, primary biliary cholangitis (low positives)
- Inflammatory bowel disease, some infections (low positives)
What symptoms go with high tTG-IgA?
- Bloating, diarrhea or constipation, weight loss, fatigue, iron deficiency
- Often none, or only anemia or low bone density
What do clinicians usually check next?
- Keep eating gluten until evaluation is complete — a gluten-free diet lowers the antibody and can hide the diagnosis
- Endomysial antibody (EMA-IgA); total IgA if not already done
- Gastroenterology referral — biopsy confirms in most adults; very high titers may allow a no-biopsy diagnosis
- Iron, ferritin, B12, folate, vitamin D, bone density once confirmed
Follow-up tests available at TestWell: Ferritin ($24.99), Folate (Vitamin B9) ($32.99).
How do you recheck tTG-IgA?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Gut Health Panel | Panel · 5 tests | $129.99 | No | 3–7 business days |
| Celiac Disease Panel | Test · 5 biomarkers | $124.99 | No | 3–7 business days |
Common questions
I went gluten-free before the test and it's negative. Am I clear?
Not necessarily — antibodies fall within weeks off gluten. A gluten challenge (several weeks of daily gluten) before retesting, or HLA-DQ2/DQ8 typing to rule celiac out, are the options.
How high does tTG-IgA have to be to diagnose celiac?
Guidelines accept a no-biopsy diagnosis in children — and increasingly in adults — when tTG-IgA is over 10× the upper limit and EMA is positive on a second sample. Lower positives need biopsy.
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.