Is HLA-DQ2 useful for allergy?

HLA-DQ2 is a genetic marker strongly associated with celiac disease (an autoimmune reaction to gluten), not with classic allergies such as pollen or food allergies. The evidence for its role in celiac disease is human-strong, but for allergies there is no robust scientific basis. Therefore, an HLA-DQ2 test is not useful for allergy assessment. Allergies are diagnosed via IgE antibodies, skin prick tests, or oral food challenges. Commercial tests marketing HLA-DQ2 as an 'allergy test' are misleading. If you suspect food intolerances, consult a physician. The evidence for HLA-DQ2 in allergy is best classified as 'practice' (based on clinical practice without strong studies) or 'unclear'.