Iron is an important trace element necessary for the production of red blood cells and adequate oxygen carrying capacity of the blood. Deficiencies can arise from either inadequate dietary intake or excessive loss of iron due to bleeding. Iron deficiency is a common cause of anemia and can result in a variety of changes in a complete blood count.

Iron Metabolism

Iron plays an important role in the development of red blood cells, muscle proteins and bones. The daily dietary requirement for iron varies with age and gender, according to the National Anemia Action Council. Men generally have an adequate dietary intake of iron, whereas younger women and children are less likely to meet requirements. Meats and seafood provide the best sources of dietary iron. Other sources of iron include eggs, dairy products and a variety of plants including beans, peas and green leafy vegetables.

Iron Deficiency

Iron deficiency occurs whenever iron intake does not match the body's needs or if the body loses iron. Childhood growth or pregnancy requires increased iron supplies, while bleeding or excessive menstruation lead to increased iron loss, both resulting in depletion of iron stores. The symptoms of deficiency are mostly related to anemia and decreased oxygen delivery to the body's tissues, as discussed by the American Society of Hematology. Symptoms include fatigue, weakness, pallor, shortness of breath with exertion, rapid heartbeat, brittle nails, hair loss and cravings for ice or dirt.

Diagnosis of Iron Deficiency

A complete blood count is typically one of the first tests performed in diagnosing iron deficiency. Decreased levels of hemoglobin, the protein in red blood cells responsible for oxygen transport, and smaller than normal red blood cells are characteristic of fully developed microcytic anemia, commonly observed with an iron deficiency, according to "Clinical Diagnosis and Management by Laboratory Methods." Additional blood tests show low iron levels, low ferritin and an increased total iron binding capacity.

Other Blood Count Changes

Anemia is the most common finding on a complete blood count in iron deficiency, but as the deficiency progresses other changes can appear. The white cell count, representing cells that protect the body from infection, is usually normal or slightly low. Platelets, responsible for assisting in blood clotting, may increase initially in iron deficiency, but often drop in number as the anemia becomes more severe. Red blood cell changes also become more apparent when viewed under the microscope, with greater variation in size, color and shape than normal.

Treatment

Iron deficiency can be treated by increasing iron in the diet or taking supplements, depending on the severity of the deficiency. The cause of the iron deficiency also needs to be determined, especially in older people or when unexplained bleeding is present. According to MedlinePlus, anemia should completely resolve after two months of iron therapy, although supplementation may be continued for up to a year to rebuild iron stores in the body.