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The TIBC Laboratory Test
The TIBC laboratory test is used to measure the total iron-binding capacity of the blood. It is ordered to detect the levels of serum iron available in a person’s blood. By using this test, a physician can determine if a patient has serum iron levels that are either too high or too low, suggesting an underlying medical condition as the reason. For example, if this test were to indicate that the TIBC level was high, this would mean that the amount of iron in the body has been reduced.
When first ordering this test, the physician will inform the person the reason why this test is being ordered, and this can be discussed with your doctor. It is mainly prescribed to diagnosed conditions such as hemochromatosis and iron-deficiency anemia. Other popular reasons for ordering this test would be in suspected liver malfunction or in kidney disease.
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TIBC and Transferrin
The total iron-binding capacity is usually stated in conjunction with transferrrin. This is a protein located in the blood that is produced in the liver, and transported around the body bound to iron. It is possible for the physician to also order a test for transferrin levels, but the TIBC levels would be reported in mcg/dl, whereas transferrin levels are measured in micromoles/L. However, both of these tests measures an increase or decrease in the amount of iron contained in the body.
To test TIBC levels, a sample of blood is taken from a vein in your arm. Before this procedure, the person will be told to fast for a minimum of eight hours before the sample of blood is to be taken. When the blood is to be taken, an elastic band or tourniquet will be placed on the upper part of the arm. A needle is then inserted into the area above the elbow. Once the needle is inserted, a sterilized vial is attached to collect the blood.
If this test is ordered, it will be important to let your physician know if you are pregnant or any medication such as oral contraceptives that can increase TIBC levels. The normal TIBC level is 240-450 mcg/dl with the transferrin level at 20-50% saturation. There is an increase in TIBC levels in pregnancy and in iron-deficiency anemia. However, a decrease is seen in cirrhosis, pernicious anemia, malnutrition, and inflammation.
Web Source: American Association for Clinical Chemistry. "TIBC & UIBC, Transferrin" 2009. Available at: http://www.labtestsonline.org/understanding/analytes/tibc/test.html