Interpretation
The presence or absence of coeliac disease-associated HLA-DQA1 and HLA-DQB1 alleles (DQ2.2, DQ2.5 and DQ8) are reported, along with the relative risk (as per the figure below). The distinction between the homozygous or heterozygous presence of the alleles, which encode the alpha- and beta-subunits of HLA-DQ2.2 and HLA-DQ2.5, allows for improved risk stratification.
The presence of a risk allele does not confer a diagnosis of coeliac disease and has low positive predictive value. Supportive evidence from coeliac serology and small intestinal histology is necessary for the diagnosis.
The absence of HLA-DQ2 and HLA-DQ8 may serve to exclude a diagnosis of coeliac disease (likelihood of coeliac disease <1%).

Test Method
This molecular genetic test uses the Euroimmun HLA-DQ2/DQ8 reverse dot blot array to determine the status of the disease-associated HLA-DQA1 and HLA-DQB1 alleles in a patient with possible celiac disease. Briefly, allele-specific primers are used to PCR amplify several sections of the HLA-DQA1 and HLA-DQB1 genes from the patient’s DNA. Once amplified, the allele-specific PCR products are hybridised to an array containing immobilised oligonucleotide probes, homologous to the amplified alleles. Only those alleles successfully amplified, and therefore present within a patient’s DNA, will hybridise and emit florescence at the particular allelic probe.