The long-term objectives of this project are to develop a non-invasive and accurate method for the measurement of mucosal uptake and transfer of iron labeled with a non-radioactive (stable) isotope for general-purpose use with hereditary hemochromatosis (HHC) patients. The method is based on ingesting a single gelatin capsule containing labeled (58Fe) ferrous sulfate, the non-absorbable marker dysprosium chloride (DyCl3), and the visual marker FD&C#1 (brilliant blue) followed by the measurement of initial mucosal uptake by analysis of a small portion of the first visually marked stool for labeled iron and Dy. Whole-body retention of absorbed labeled iron is measured from either incorporation of the ingested isotope in circulating red cells, or measured of the ratio for 58Fe/57Fe in plasma 1-3 hours after injection of a small dose of 57 Fe- transferrin concurrently with the oral dose. The specific aims of the proposed phase-I research are to demonstrate the feasibility of this approach in ten patients with uncomplicated iron-deficiency. PROPOSED COMMERCIAL APPLICATIONS: This research will lead to a method for routine use in hemochromatosis patients. It has applications in confirming diagnosis, predicting prognosis, and many aspects of hemochromatosis research.