Interpretation
Taken together with serum iron and percent transferrin saturation clinicians usually perform this test when they are concerned about anemia, iron deficiency or iron deficiency anemia. However, because the liver produces transferrin, alterations in function (such as cirrhosis, hepatitis, or liver failure) must be considered when performing this test. It can also be an indirect test of liver function, but is rarely used for this purpose.
The percent transferrin saturation (i.e., the result of the formula of serum iron/TIBC x 100) can also be a useful indicator.
| Condition | Serum iron | Transferrin and TIBC | Percent transferrin saturation |
|---|---|---|---|
| iron deficiency anemia | Low | High. The liver produces more transferrin, presumably attempting to maximize use of the little iron that is available. | Low, as there is insufficient iron. |
| anemia of chronic disease | Low, as the body holds iron intracellularly with ferritin. | Low. The body produces less transferrin (but more ferritin), presumably to keep iron away from pathogens that require it for their metabolism. This is mainly regulated by increased hepcidin production. | Normal |
| pregnancy or use of hormonal contraception, but without iron deficiency | Normal | High. The liver increases the production of transferrin, thus raising TIBC. | Low, as there is excess transferrin with normal serum iron levels. |
These examples demonstrate that to properly understand a value for TIBC, one also must know the serum iron, the percent transferrin saturation, and the individual clinical situation.
Read more about this topic: Total Iron-binding Capacity