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Immunoassay for Anti-Tissue Transglutaminase Antibodies (Serum/Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the presence of antibodies against tissue transglutaminase, a protein involved in gluten metabolism. It helps diagnose celiac disease, an autoimmune condition triggered by gluten.

Quick summary

["This test helps identify celiac disease by detecting antibodies linked to gluten sensitivity."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
56886-5
Short code
IAT Titr SerPl
Synonyms
IAT Titr SerPl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may recommend this test if you have symptoms like persistent diarrhea, stomach pain, weight loss, or fatigue, especially if you’ve been diagnosed with gluten sensitivity or have a family history of celiac disease. It’s also used to confirm a diagnosis after a gluten-free diet trial.

What Does a Positive Result Mean?

A positive result strongly suggests celiac disease, as these antibodies attack gluten in the small intestine. However, a negative result doesn’t rule out the condition—other tests or a gluten-free trial may be needed for confirmation.

What to Expect Before the Test

No special preparation is usually required, but if you’re being tested for celiac disease, your doctor may ask you to temporarily avoid gluten-containing foods (like wheat, barley, or rye) for 4–6 weeks before testing to ensure accurate results.

What Happens During the Test?

A blood sample is drawn from a vein in your arm. The sample is sent to a lab for testing using an immunoassay method, which detects the antibodies in your serum or plasma.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Anti-TTG Antibodies (IgA)

Frequently asked questions

Can this test be affected by diet?
Yes, if you’ve recently eaten gluten, it may increase antibody levels. That’s why doctors often recommend avoiding gluten for a few weeks before testing to get the most accurate result.
What if my test results are unclear?
If your results are borderline or negative, your doctor may repeat the test after you’ve followed a gluten-free diet for several months. They may also recommend additional tests, like an endoscopy or genetic testing for HLA-DQ2/DQ8 genes.
Is this test painful?
The blood draw itself is minor and usually causes only mild discomfort. Most people feel fine afterward, though some may experience a slight bruise or soreness at the injection site.
  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 16, 2026. · Read our editorial policy