Total Iron Binding Capacity (TIBC)

Iron is a mineral that plays a vital role in healthy functioning of the body. A substantial amount of iron is present in the form of hemoglobin (an oxygen carrying protein) and the majority of the remaining iron is stored by an intracellular protein called ferritin. Since iron is required for various vital bodily processes, one is most likely to experience distressing symptoms if the levels of iron are below or above the normal range.

While a complete blood test can provide one with information on hemoglobin levels, the levels of iron in the body can be measured with the help of certain diagnostic tests. Total iron binding capacity (TIBC) is one such test that provides useful information on amount of iron that is bound and carried into the blood through a glycoprotein called transferrin.

Here is some information on the possible causes of low or high TIBC.

TIBC test is mostly conducted along with a serum iron test. The serum iron test is another blood test that is conducted in order to measure the amount of transferrin-bound iron that is circulating in the blood. The TIBC and serum iron levels are both required for measuring the transferrin-iron saturation percentage.

The transferrin-iron saturation is obtained by multiplying the ratio of serum iron and TIBC by 100. Unsaturated iron binding capacity refers to the value that one gets by subtracting serum iron from the total iron binding capacity. It basically refers to the amount of transferrin that is not used for transporting iron in the blood.

The levels of ferritin can also be measured through a blood test. Ferritin stores iron and releases it into the blood as and when needed. There is an inverse relationship between ferritin and TIBC levels. When the iron stores or the ferritin levels are high, TIBC would be low.

Most of these tests are usually ordered when a person is exhibiting signs that indicate abnormal levels of iron in the body. The doctors may first order a complete blood count (CBC), and if the value of hemoglobin in CBC is not within the normal range, they may order TIBC and serum iron test.

In case of a healthy individual, TIBC must lie anywhere between 240 to 450 micrograms per deciliter. While the TIBC value is usually higher than the normal range in case of people suffering from iron deficiency anemia, other indicators of iron deficiency anemia include low iron saturation and low serum iron levels.

Elevated TIBC may also be seen in pregnant women. High levels during pregnancy are mainly attributed to the increased production of transferrin by the liver. On the other hand, TIBC is lower than the normal range in case of people suffering from hemochromatosis.

Hemochromatosis is a medical condition wherein the amount of iron stored by the body is way higher than the body's requirements. This gives rise to the accumulation of iron in the tissues or organs. TIBC may also be lower in people suffering from anemia due to a chronic disease. More often than not, poor dietary habits are responsible for causing iron deficiency anemia. People suffering from bowel disease may also suffer from an iron deficiency anemia due to malabsorption of iron.

A person suffering from an iron deficiency anemia is most likely to suffer from low energy levels, fatigue, headaches, pale skin and lightheadedness. The best way to alleviate the symptoms of iron deficiency anemia is to follow a healthy diet that contains foods rich in iron. One can also take iron supplements. It is also essential to consume foods that promote the absorption of iron, and refrain from having foods that inhibit the absorption of iron.

Foods that are rich in vitamin C help in absorption of iron, while excessive intake of calcium-rich foods may have an adverse effect on the body's ability to absorb iron. While anemia causes a pale skin, iron overload or hemochromatosis causes abnormal pigmentation of the skin.

One may also suffer from low energy levels, joint pain and abdominal pain. If left untreated, organs such as the heart, liver or pancreas may get affected. If one is diagnosed with this condition, the treatment would involve the removal of excess iron through phlebotomy (removal of blood).

This was some information on what is TIBC and what does an elevated or low TIBC signify. Blood tests such as TIBC and serum iron test can provide valuable information that may help doctors in the differential diagnosis of anemia caused by an iron deficiency or other conditions. The clinical significance of these tests cannot be stressed enough.