The frequency of type 1 diabetes mellitus (T1DM)-associated HLA DQ alleles in the U.S. Pacific Northwest is as high as in Scandinavia, which has the highest T1DM incidence in the world. The high regional rate of islet autoimmunity observed among DPT-1 relatives supports this notion. Fortunately, Washington State archives dried blood spots after legislature-mandated newborn screening. The Diabetes Evaluation in Washington (DEW-IT) study aims to show that population-based prospective prediction of T1DM by HLA genotype screening followed by autoantibody surveillance can be performed within the public health infrastructure.