The following information was provided by the Patient Information Service of the Aplastic Anemia & MDS International Foundation
The normal amount of iron in the body is 3 to 7 grams, some in the form of hemoglobin in circulating red cells, some in iron-containing proteins such as myoglobin, some as iron bound to transferrin in plasma, and some storage iron in the form of ferritin or hemosiderin. Adult men have about 1 gram of storage iron, mostly in the liver, spleen, and bone marrow, while adult women have less.
As to toxicity, normal serum ferritin range is 15-160 ng/ml. According to the AA&MDSIF iron overload fact sheet, by Dr. Pamela Becker, "once serum ferritin levels reach 1,000 to 2,000 ng/ml it is time to initiate a form of chelation. However, other tests help confirm need for chelation - serum iron level, serum total iron binding capacity, serum transferring level, and some type of direct assessment of the tissue iron stores."
Doctors differ over when to initiate treatment. Some initiate chelation when iron ferritin is over 1000 ng/ml or patients have received 20+ units of blood. Some chelate only when a patient is symptomatic, partly because they don’t want to introduce more drugs unless/until a patient is stable, and partly because they think the non-invasive, serum measuring tests are not precise enough.