HLA DQ2/DQ8

Key points

• HLA-DQ2 and/or DQ8 are present in almost all patients with coeliac disease
• a negative result has a very high negative predictive value and can be used to help rule out coeliac disease in equivocal cases
• up to a third of the general population also carry these alleles, so a positive result alone does not confirm the diagnosis
• Drug (olmesartan) induced enteropathy is a differential for villous atrophy with negative coeliac serology