The Anti-Deamidated Gliadin Peptide IgG (DGP IgG) test detects antibodies in your blood against modified gluten proteins, helping diagnose celiac disease or gluten sensitivity, especially useful in young children or those with IgA deficiency, by identifying the immune response to gluten when consumed. A positive result suggests celiac disease, but a small bowel biopsy is needed for confirmation, and the test must be done while eating gluten