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Deamidated Gliadin Peptide (DGP) IgA

An antibody test for celiac disease that looks for IgA antibodies to a modified gluten protein. It is usually a second-line test, with tTG-IgA used first.

AI-verified against cited sources. Awaiting expert reviewAlso called DGP IgA, DGP-IgALOINC 58709-7

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What it is

Gliadin is a protein in gluten, which is found in wheat, barley and rye. In celiac disease, a gut enzyme called tTG changes (deamidates) gliadin, and the immune system makes antibodies against the changed form. This test measures IgA antibodies to deamidated gliadin peptides in your serum. Results are reported in units, and the ranges depend on the kit your lab uses.

Why it matters

Celiac blood tests help a clinician decide whether a small-bowel biopsy is needed. The tTG-IgA test is usually the first choice. The 2020 ESPGHAN guideline advises against DGP for first-line testing. Some labs still include DGP, for example in profiles for children under 2. A positive result makes celiac disease more likely. It is not enough alone, and a biopsy is usually needed to confirm it.

If it’s high

A high DGP IgA means IgA antibodies to a modified gluten protein were found. This makes celiac disease more likely. A small-bowel biopsy is usually the next step to confirm it. Some people without celiac disease also have a positive result. Some people with celiac disease test negative, especially if they already avoid gluten or have low IgA.

Common causes

  • Celiac disease
  • Dermatitis herpetiformis, an itchy, blistering skin rash linked to gluten
  • A positive result in a person who does not have celiac disease

What can help

  • Ask your clinician before cutting out gluten, because a gluten-free diet can make celiac blood tests look negative
  • Ask whether a small-bowel biopsy or other celiac tests, such as tTG-IgA and total IgA, are needed
  • If celiac disease is confirmed, ask about working with a dietitian who knows celiac disease

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: 0–20 U/mL. Source: Mayo Clinic Laboratories.

Mayo Clinic Laboratories ELISA categories (weak positive includes 30.0)

  • Negativebelow 20 U/mL
  • Weak positive20 to under 30 U/mL
  • Positive30 and above U/mL

What can affect your result

  • Gluten intake: levels can fall, and the test can turn negative, on a gluten-free diet
  • IgA deficiency: low IgA can cause a falsely negative IgA-based test, so total IgA is often checked
  • Age: Labcorp recommends a celiac profile that includes DGP for children younger than 2
  • The kit used: units and cutoffs differ between assays
  • A gluten-free diet before the test can make the result negative even when celiac disease is present (Mayo).
  • Low or missing IgA (IgA deficiency) can make an IgA-based test negative. Mayo advises considering IgA deficiency when this test is negative and checking total IgA.
  • Units and cutoffs depend on the kit. Mayo uses an ELISA, and Labcorp uses a Thermo Fisher EliA fluoroenzyme immunoassay, so numbers from different labs cannot be compared directly.
  • Labcorp rejects hemolyzed, lipemic or bacterially contaminated samples.

Levels may begin to fall after a strict gluten-free diet starts and keep falling with time, but how fast varies from person to person.

When to talk to a clinician

Talk with a clinician about long-lasting diarrhea, belly pain or bloating, unexplained weight loss, low iron or anemia that does not improve, or an itchy blistering rash, especially if a celiac test is positive. In children, slow growth is another reason to check in. Get urgent care for severe belly pain or signs of dehydration.

Questions you could ask

  • Why was a DGP test added in my case?
  • Do I need a small-bowel biopsy to confirm this?
  • Should my total IgA and tTG-IgA be checked too?
  • Should I keep eating gluten until all testing is done?

Questions people ask

Why was a DGP test added to my celiac tests?

Some labs include DGP in celiac profiles, for example for children under 2. An IgG version is used when IgA is low or missing. Guidelines differ. The 2020 ESPGHAN guideline advises against DGP as a first test, while Labcorp recommends a profile that includes it for children under 2.

Should I stop eating gluten before the test?

No. Antibody levels can fall on a gluten-free diet, which can make results look negative when celiac disease is present. Talk with your clinician before changing your diet.

What does a weak positive mean?

Some labs use extra categories. At Mayo Clinic Laboratories, 20.0 to 30.0 U is called weak positive and above 30.0 U is called positive. Cutoffs differ by kit. Your clinician will weigh the result with your other celiac tests and symptoms.

Show the science and sources

For clinicians and researchers

DGP assays use synthetic deamidated gliadin peptides as the antigen. The 2020 ESPGHAN guideline recommends against DGP-IgG and DGP-IgA for initial testing and favors total IgA with tTG-IgA; only if total IgA is low or undetectable is an IgG-based test indicated. The 2023 ACG update names tissue transglutaminase antibodies as the example test for initial screening. Mayo's ELISA reports negative below 20.0 U, weak positive 20.0-30.0 U and positive above 30.0 U for all ages. Labcorp measures DGP IgA and IgG by Thermo Fisher EliA fluoroenzyme immunoassay in its celiac profiles and recommends a profile that includes DGP for children under 2. Cutoffs, units and categories are kit-specific and not interchangeable. Antibody levels can fall on a gluten-free diet, and a negative result in someone who has already stopped gluten does not exclude celiac disease. Total IgA should be known when interpreting IgA-based tests. ARUP uses a multiplex particle-based assay (PMAT) with a 0.00-4.99 FLU interval, which is not interchangeable with U. Labcorp reports result LOINC 58709-7 (units), Mayo reports 47393-4 (presence) and ARUP reports 63453-5 (immunoassay units).

LOINC 58709-7 (primary), 63453-5, 47393-4. Specimen: serum.

Sources

  1. Gliadin (Deamidated) Antibody, IgA, Serum (test DAGL), Mayo Clinic Laboratories
  2. Celiac Antibodies Profile tTG IgA, tTG IgG, DGP IgA, DGP IgG, and Total IgA (test 164010), Labcorp
  3. Exploring Celiac Disease (testing options), Labcorp
  4. European Society Paediatric Gastroenterology, Hepatology and Nutrition Guidelines for Diagnosing Coeliac Disease 2020, Journal of Pediatric Gastroenterology and Nutrition (ESPGHAN) (2020)
  5. American College of Gastroenterology Guidelines Update: Diagnosis and Management of Celiac Disease, American Journal of Gastroenterology (ACG) (2023)
  6. Deamidated Gliadin Peptide (DGP) Antibodies, IgA and IgG (test 0051358), ARUP Laboratories
  7. LOINC codes and long common names verified with the NLM Clinical Tables LOINC search, U.S. National Library of Medicine

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

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