TIBC stands for total iron binding capacity. Although it is not the only test done, it is used to measure iron levels in the body. It is ordered if iron deficiency is a possibility, or if an iron overload may be occurring. The procedure is considered a simple laboratory test. It is performed by drawing a blood sample from a vein and having it analyzed in the lab.
It is important to understand the total iron binding capacity is not the concentration of iron in the blood. That measurement is obtained from a serum iron test. In the blood, iron is carried by the protein transferrin. The TIBC measures how well the protein binds to the iron. Usually both the serum iron test and total iron binding capacity are ordered to have an accurate measurement of iron levels.
A normal total iron binding capacity is 240-450 micrograms per deciliter(mcg/dL). If the levels of iron in the blood are lower than normal, the TIBC will be higher than normal. If the amount of iron in the blood is higher than normal, the TIBC is lower than normal.
There are several causes of abnormal results. Elevated TIBC and low iron levels are usually caused by anemia. If a patient has symptoms of anemia, such as weakness, headaches, and fatigue, a TIBC will usually be ordered. Iron in the body can also become low during the end of pregnancy, and the test may be recommended. Higher than normal iron levels, causing a low TIBC may be caused by medical conditions, such as liver disease, sickle cell anemia, and malnutrition.
Results may not always be accurate with only a total iron binding capacity test. Inflammation in the body can lead to lower-than-normal results. Certain medications, such as birth control pills, may also interfere with the results. In some cases, results may also be normal even when abnormal conditions are present, such as in iron poisoning.
The only special preparation before a total iron binding capacity test is to refrain from eating or drinking anything for eight hours before the test. The test is performed similarly to other blood draws. A needle is inserted into the vein, obtaining a small amount of blood.
There are very few risks for the procedure. As with other blood draws, complications are rare. Very rarely, an infection can develop at the puncture site or excessive blood can pool, causing swelling.