Anti-DGP IgG (deamidated gliadin peptide IgG antibody) is a blood test used in the diagnosis of coeliac disease. It detects IgG-class antibodies produced against deamidated forms of gliadin — a component of gluten. Unlike standard gliadin antibody tests, anti-DGP antibodies target modified gliadin peptides that more specifically reflect the immune response occurring in coeliac disease.

Anti-DGP IgG is most valuable in people with IgA deficiency, which affects approximately 1 in 600 people. Because the standard coeliac screening test (tTG IgA) relies on IgA antibodies, it gives a false-negative result in IgA-deficient individuals even when coeliac disease is present. Anti-DGP IgG provides an IgA-independent alternative, ensuring coeliac disease is not missed in this group. It is also used in children under two years, in whom tTG IgA may be less reliable.