The study has two specific aims, as follow: (1) to develop guidelines for the use of transferrin saturation and related tests in detection of individuals at risk for hemochromatosis, and (2) to determine the frequency of the gene for hemochromatosis in the United States by statistical mixture modeling of population transferrin saturation data from NHANES III. Providing the statistical foundation for the analysis of transferrin saturations should facilitate development of optimal, cost-effective screening regimens for identification of individuals requiring further evaluation for hemochromatosis.