Iron Tests

Iron is an essential nutrient. It is needed in small quantities to help form normal red blood cells (RBCs). Iron is a critical part of hemoglobin, the protein in red blood cells that binds oxygen in the lungs and releases it as blood travels to other parts of the body. Low iron levels can lead to anemia and the production of RBCs that are microcytic and hypochromic. Large quantities of iron can be toxic to the body, and absorption of too much iron over time can lead to the accumulation of iron compounds in organs and tissues. This can damage organs such as the liver, heart, and pancreas.

Iron is normally absorbed from food and transported throughout the body by transferrin, a protein produced by the liver. About 70% of the iron transported is incorporated into the hemoglobin inside RBCs. Most of the rest of it is stored in the tissues as ferritin or hemosiderin, and small amounts of it are used to produce other proteins such as myoglobin, and some enzymes.

Iron tests evaluate the amount of iron in the body by measuring several substances in the blood. These tests are often ordered at the same time and the results considered together to help diagnose and/or monitor iron deficiency or iron overload.

Iron deficiency may be seen with insufficient intake, inadequate absorption, or increased requirements, such as may be seen during pregnancy or with acute or chronic blood loss. Iron overload may be acute or chronic. Acute iron poisoning may occur, especially in children, with the ingestion of iron tablets. Chronic overload may be due to excessive intake, hereditary hemochromatosis and multiple blood transfusions or due to other conditions.

A blood sample is drawn by needle from a vein in your arm.

Your doctor may request that you fast for 12 hours prior to some iron tests. In this case, only water is permitted.