Iron and total iron-binding capacity (TIBC) are measured together to identify how much iron is being carried in the blood. In persons with anemia, these tests can help to determine whether it is due to iron deficiency or another cause, such as chronic illness.
These same two tests are also used to screen for hereditary hemochromatosis. The College of American Pathologists recommends screening for hemochromatosis in all people over age 20 because of the low cost of diagnosis and treatment if caught early. Other organizations have not yet recommended screening because it is not yet possible to tell which persons who have the abnormal genes will never develop symptoms and which will develop organ damage. A number of studies are currently underway to develop a strategy to determine when and how to screen people.
Iron tests are not ordered routinely. If hemoglobin and hematocrit are abnormally low, however, iron tests can be very useful in determining the cause of anemia. Iron tests can also be used when iron deficiency is being treated to tell if the iron is being absorbed properly and to detect when enough iron has been taken. The test also may be ordered when your doctor suspects you may have too much iron. If you have symptoms that could be due to hemochromatosis, iron tests represent the best way to determine whether this could be the diagnosis. In a child who has ingested iron tablets, iron levels are the only way to determine the severity of poisoning.
What does the test result mean? NOTE: This test has no single number that identifies an abnormal result.
Your lab report (see a sample report) should include
a range of numbers (reference range) that identifies what is expected for you based on
your age, sex, and the method used in that laboratory. You can find more information
about expected results at Reference Ranges
and What They Mean. Lab Tests Online strongly recommends that you discuss the meaning of your test results with your doctor.
A low iron with a high transferrin or TIBC is usually due to iron deficiency. In chronic diseases, both iron and transferrin or TIBC are typically low. Low iron can cause anemia and is usually due to long-term or heavy bleeding, pregnancy, rapid growth (in children), or an iron-poor poor diet.
Samples for iron should be taken in the morning, before you have had any food to eat. You should not take any iron pills or tablets for 24 hours before the test. Iron is absorbed rapidly from food or pills and can make your iron levels falsely high.
This article was last reviewed on March 10, 2006.
This page was last modified on April 8, 2009.
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