Iron is needed for a number of chemical reactions in the body. It is found most attached to the protein hemoglobin, which is an abundant protein packed into red blood cells, responsible for carrying oxygen through blood to the tissues. Iron levels are measured in a number of ways that elucidate not only the level of iron in the blood but reasons for high or low levels. It is important to consult with a physician for the diagnosis and treatment of iron disorders.
Serum Iron
Serum iron is the measure of iron in the serum, which is the liquid component of blood, or the whole blood minus the white and red cells. Normal serum iron ranges from about 65 to about 175 mcg/dL in men, 50 to 170 mcg/dL in women, 50 to 120 mcg/dL in children and 100 to 250 mcg/dL in newborns.
Ferritin
Ferritin is a protein found in cells that stores iron. Iron is stored in complex with a protein because free iron can be to toxic to cells. Levels of ferritin are directly correlated to the total level of iron in the body. Low levels indicate a low level of iron. High levels indicate inflammation or a disorder of iron overload.
Transferrin
Transferrin is a protein that transports iron through the body. The total iron binding capacity or TIBC measures the available protein that can bind iron. In certain diseases the transferrin level may be higher or lower, independent of the level of iron in the body. For example, in iron deficiency anemia, low iron stores cause abnormal development of red blood cells, and high levels of transferrin to transport all iron available. In anemia, or chronic disease, the storage levels of iron are high, but the transferrin levels are low, so that iron is not available to to the body.
Blood Cells
Since about 60 percent of the iron in the body is used by red blood cells, they are profoundly affected by low iron levels. Anemia, or low red blood cell counts, is frequently caused by iron deficiency. Studies of the red blood cells can reveal problems with iron. For example, the size of the red blood cells in anemia can be indicative of low iron. Small red blood cells that are few in number and variable in size, called a microcytic anemia with anisocytosis, indicate low iron.
References
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, et al.; 8th Ed 2009
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci, et al.; 17th Ed 2008
- "Physiology"; Linda S.Costanzo; 4th Ed 2008
- "Henry's Clinical Diagnosis and Management by Laboratory Methods"; Richard A. McPherson, et al.; 21st Ed 2006
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