XeliGen XL is a real time PCR test for the determination of the susceptibility to celiac disease and for the stratification of the risk of developing the disease into five genetic risk classes (G1-G5) by amplification of specific HLA alleles from peripheral blood and buccal swab. The test detects all the possible genotypes, including the rarest ones, by direct detection of all the alleles of the DQA1 and DQB1 loci or by ad hoc linkage disequilibrium, for a total of 300 combinations including homozygosity, represented by HLA haplotypes DQ2 and DQ8, as well as DQ4, DQ5, DQ6, DQ7, DQ9.