Deamidated Gliadin Peptide Antibody, IgG (DGP IgG)
Other marker
Deamidated Gliadin Antibody IgG
Deamidated Gliadin Peptide Antibody, IgG (DGP IgG)
An antibody test used in the diagnosis of coeliac disease. It detects IgG antibodies against deamidated gliadin peptides, a component of gluten. It is especially valuable because it works even in people who are IgA-deficient, in whom the standard IgA-based coeliac tests can be falsely negative.
PED Notes
Gut symptoms, bloating, and unexplained fatigue or anaemia are common complaints in dieting athletes, and coeliac disease is an under-recognised cause. This IgG-based test is the go-to when total IgA is low (selective IgA deficiency makes tTG-IgA and endomysial IgA unreliable). For accurate results the person must be eating gluten in the weeks before testing; a self-imposed gluten-free diet, common among physique athletes, can normalise the antibodies and hide the diagnosis.
When high
When elevated (>20 U/mL, positive):
- Suggests coeliac disease, particularly useful when IgA is deficient; it is often ordered together with tissue transglutaminase IgA and total IgA
- A positive result should be confirmed. The diagnostic standard in adults is duodenal biopsy while still consuming gluten; do not start a gluten-free diet until the workup is complete, or you risk masking the diagnosis
- Correlate with symptoms (diarrhoea, bloating, weight changes), iron-deficiency anaemia, and low vitamin D or B12, which often accompany coeliac malabsorption
Action: Keep eating gluten, get referred to gastroenterology for confirmatory testing, and only adopt a strict gluten-free diet once coeliac disease is confirmed or excluded.
When low
When negative (within range):
- A negative result makes coeliac disease unlikely, provided the person was eating gluten at the time of testing
- If symptoms persist despite a negative result, ensure gluten was being consumed, consider retesting, and evaluate for non-coeliac gluten sensitivity or other gastrointestinal causes
History Chart
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Frequently Asked Questions
Reference Ranges
Standard Range