<p>Hyperphosphatemia in chronic kidney disease on dialysis: Ferric iron binds dietary phosphate in the GI tract and precipitates as ferric phosphate. This compound is insoluble and is excreted in the stool. By binding phosphate in the GI tract and decreasing absorption, ferric citrate lowers the phosphate concentration in the serum.<br />
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Iron deficiency anemia in chronic kidney disease not on dialysis: Ferric iron is reduced from the ferric to the ferrous form by ferric reductase in the GI tract. After transport through the enterocytes into the blood, oxidized ferric iron circulates bound to the plasma protein transferrin, and can be incorporated into hemoglobin.</p>