Iron (Fe) is an element that is an important component of hemoglobin in red blood cells.  Hemoglobin transports oxygen from the lungs to all the cells of the body.  Most of the iron in the body is located in hemoglobin, but some iron is located in myoglobin as well as some iron is stored in the liver, bone marrow, and spleen.  The storage form of iron is ferritin.  Iron is transported in the blood by a protein called transferrin.