Iron and Total Iron-Binding Capacity
Do these tests have other names?
Iron (Fe), serum iron, TIBC
What are these tests?
The serum iron test measure the amount of iron in your blood. The total iron-binding
capacity (TIBC) test looks at how well the iron moves through your body.
Iron is an important mineral that your body needs to stay healthy. Your body uses
iron to make hemoglobin, the protein in your red blood cells that carries oxygen throughout
your body. If you don't have enough iron, you may not have enough hemoglobin. This
condition is called iron deficiency anemia.
Iron in your body is carried, or bound, mainly to a protein made by your liver called
transferrin. The TIBC test is based on certain proteins, including transferrin, found
in the blood. Your transferrin levels are almost always measured along with iron and
Why do I need these tests?
You may need these tests if your healthcare provider thinks your iron level is too
low or too high. Not having enough iron in your diet is the most common cause of anemia
and the most common type of diet deficiency in the U.S. Your healthcare provider may
do this test to look at your diet, nutrition, liver, or other conditions that cause
iron to be low, such as increased blood loss or pregnancy.
Symptoms of iron deficiency include:
Being tired and feeling weak
Getting frequent infections
Feeling cold all the time
Having swelling in the tongue
Struggling to keep up at school or work
In children, having delayed mental development
Symptoms of too much iron can include:
Feeling tired and weak
What other tests might I have along with these tests?
Iron, TIBC, and transferrin blood tests are almost always done together. Other blood
tests that may also be done include measuring your hemoglobin; your percent of red
blood cells, or hematocrit; and all the cells in your blood, called a complete blood
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses
to do the test. Even if your test results are different from the normal value, you
may not have a problem. To learn what the results mean for you, talk with your healthcare
Normal results of iron testing may be different for men, women, and children. Iron
and TIBC are measured in micrograms per deciliter (mcg/dL). Normal results for iron
Normal results for TIBC are 250 to 450 mcg/dL for men and women.
Some common conditions that may cause the amount of iron in your blood to be too low
Some common conditions that may cause the amount of iron in your blood to be too high
Conditions that cause red blood cells to die, called hemolytic anemia
Iron or lead poisoning
Iron overload, such as from hemochromatosis
Many blood transfusions
Your healthcare provider will look at your iron level in conjunction with the TIBC,
transferrin, and possibly other tests to better understand what the results mean.
How are these tests done?
The test requires a blood sample, which is drawn through a needle from a vein in your
Do these tests pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection,
bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight
stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Many medicines can affect the results of these blood tests. Some common medicines
that may affect your results include alcohol, birth control pills, antibiotics, aspirin,
estrogen, and testosterone. Women who are having their menstrual period may have decreased
How do I get ready for these tests?
You may be asked to have these blood tests in the morning after fasting overnight.
Normally, iron levels are closest to normal in the morning and get lower as the day
goes on. Be sure your healthcare provider knows about all medicines, herbs, vitamins,
and supplements you are taking. This includes medicines that don't need a prescription
and any illicit drugs you may use.