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IgA Antibodies to Tissue Transglutaminase (IgA tTG) - Serology

Published: August 9, 2026Updated: August 15, 2026

This test measures antibodies in your blood that may indicate celiac disease, an autoimmune condition triggered by gluten. It helps doctors diagnose whether gluten is causing damage to your small intestine.

Quick summary

["This test can help determine if you have celiac disease by detecting specific antibodies linked to gluten sensitivity."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
94493-4
Short code
CDPANEL
Synonyms
Celiac IgA + HLA + Sero Bld/T
Category
chemistry
Sample
serum
Container
Serum separator tube (SST, tiger-top, gold-top) or red-top tube for serology; EDTA (purple-top) or ACD (yellow-top) tube for HLA typing
Units
N/A
Ref low
4
Ref high
10
Fasting
false
Population
adult
Sex
all
Age range
≥ 2 years
Method
Enzyme-linked immunosorbent assay (ELISA) for tissue transglutaminase IgA and anti-endomysial IgA antibodies; total IgA measurement; polymerase chain reaction (PCR) with sequence-specific oligonucleotide probes (SSOP) or sequence-based typing (SBT) for HLA-DQ2 and HLA-DQ8 alleles
CPT
83516 (tTG IgA); 86256 (EMA IgA); 82784 (total IgA); 81382 (HLA Class II typing, high resolution)
SNOMED
713844000
Specimen volume
5-10 mL whole blood total; minimum 2 mL serum required for serology panel; 3-5 mL EDTA whole blood for HLA typing
Stability
Serum: Room temperature up to 8 hours; refrigerated (2-8°C) up to 7 days; frozen (-20°C or below) up to 6 months for serology. EDTA whole blood for HLA typing: Room temperature up to 48 hours; refrigerated (2-8°C) up to 7 days; do not freeze whole blood for HLA typing as it may compromise DNA integrity.
Hemolysis max
100
Lipemia max
50
Icterus max
25
TAT
24–168 hours
Order
routine

Why This Test Is Done

Your doctor may recommend this test if you have symptoms like persistent diarrhea, stomach pain, fatigue, or unexplained weight loss. It’s also used when other tests suggest possible celiac disease, especially if you’ve been diagnosed with gluten-related disorders or have a family history of celiac disease.

How the Test Works

A small blood sample is taken from your arm. The sample is tested for the presence of IgA antibodies to tissue transglutaminase, a protein that reacts with gluten. This helps identify if your immune system is attacking the lining of your small intestine due to gluten exposure.

What to Expect Before the Test

No special preparation is needed for this test. However, if you’re being tested for celiac disease, your doctor may ask you to follow a gluten-free diet for a few weeks before the test to ensure accurate results.

What the Results Mean

Positive results suggest a high likelihood of celiac disease, but further testing (such as a biopsy of your small intestine) may still be needed to confirm the diagnosis. Negative results mean you likely do not have celiac disease based on this antibody test alone.

Reference range

Tissue Transglutaminase (tTG) IgA: Negative (<4.0 U/mL or <20 U/mL depending on assay); Equivocal (4.0-10.0 U/mL); Positive (>10.0 U/mL). Anti-Endomysial IgA (EMA): Negative (titer <1:5 or <1:10). Total IgA: 70-400 mg/dL (adult). HLA-DQ2: Negative; HLA-DQ8: Negative. Results should be interpreted in conjunction with clinical findings and duodenal biopsy when indicated.N/A

Specimen: serum

No special preparation required. Patient should continue a normal gluten-containing diet prior to testing, as serological markers may become falsely negative if gluten has been eliminated from the diet prior to testing. Patients who have already initiated a gluten-free diet should be informed that serology may be unreliable and a gluten challenge may be necessary.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Celiac disease can cause long-term damage to the small intestine if left untreated, leading to nutrient deficiencies, chronic digestive issues, and other health problems. Early diagnosis through antibody testing and follow-up can help manage symptoms and prevent complications by guiding a gluten-free diet and medical care.

Short name

IgA tTG Antibody Test

Frequently asked questions

What does a positive result mean?
A positive result strongly suggests celiac disease, but doctors will often perform additional tests, like an endoscopy with a small intestine biopsy, to confirm the diagnosis. This helps rule out other conditions and ensures proper treatment.
Can I eat gluten before this test?
If your doctor recommends it, you may need to avoid gluten for a few weeks before testing to get the most accurate results. Always follow your healthcare provider’s instructions.
Is this test painful?
The test involves a simple blood draw, which may cause slight discomfort for a few seconds. Most people find it brief and manageable, similar to other routine blood tests.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 15, 2026. · Read our editorial policy