Statistical mixture modeling was used to develop guidelines for hemochromatosis screening regimes and to determine the frequency of the gene for hemochromatosis. The research was designed to provide a statistical foundation for the analysis of population transferrin saturations to assist in development of optimal screening regimens for hemochromatosis. To determine potential screening thresholds, probability methods were applied to data from the third National Health and Nutrition Examination Survey (NHANES III), a cross-sectional probability sample weighted to represent the U.S. population. Statistical mixture modeling was used to determine potential transferrin saturation screening thresholds to identify individuals for repeat testing and possible further evaluation. The actual sensitivity and specificity of these screening thresholds was then assessed using data from a separate demonstration project, "Cost effective Hemochromatosis Survey in Primary Care", designed to identify individuals with hemochromatosis. In addition, the gene frequency for hemochromatosis for whites and ethnic subgroups was also determined by analysis of transferrin saturation data from NHANES III.