The serum iron test is used to measure the amount of iron that is in transit in the body and is useful to detect and diagnose iron deficiency or iron overload.
Iron is a nutrient that is required for the production of red blood cells (RBCs). It is a critical part of haemoglobin that is responsible for binding oxygen to the RBC for transport from the lungs to other parts of the body. The test measures the serum iron level.
Serum iron is mostly ordered with other iron-related tests such as serum ferritin and haemoglobin to assess the iron deficiency or overload and monitor the response to treatment.
Iron is essential to produce red blood cells. Iron is not produced by the body but must be absorbed from either food sources or supplements. Absorbed iron is incorporated into haemoglobin of the red blood cells. Excess iron is stored as ferritin or hemosiderin in body tissue like liver, spleen, bone marrow and muscles. When iron is short (insufficient) to meet the body requirements the iron level in the blood will drop and the iron stores will become depleted thus decreasing the ferritin level.
The causes for becoming iron insufficient include:
Complications can arise form longstanding iron shortage including a decreased amount of haemoglobin called iron deficiency anaemia. Symptoms of iron shortage of the only develops later when anaemia sets in and include fatigue, general weakness, dizziness, headaches and a pale skin.
Iron storage also increase in the event that more iron is absorbed than required and over time can cause excess deposition in organs as is seen in the genetic condition called haemochromatosis. Iron overload can occur in patients that receive many blood transfusions or intravenous iron supplementation.
A serum Iron test is usually ordered when a person develops signs and symptoms of iron-deficiency anaemia including:
The test is also ordered when there the haemoglobin level is low and together with other iron tests used to establish a diagnosis of iron deficiency anaemia.