The initial screen for recruitment into The Environmental Determinants of Diabetes in the Young (TEDDY) is identification of certain higher-risk haplotypes at HLA-DR and -DQ loci. Different centers will use different laboratory methods and algorithms to identify these higher-risk haplotypes. To insure between-center comparability in this screening, CDC will conduct annual qualification challenges using cord bloods and dried blood spots with pre-established reference haplotypes.
