Transferrin is a direct measure of the iron binding capacity. Transferrin is thus useful in assessing iron balance. Iron deficiency and overload are often evaluated with complementary laboratory tests.
Transferrin saturation, like TIBC/UIBC, is a measure of iron storage. The higher the level within a health screening, the greater the amount of iron stored. This test can be used to detect iron deficiency, and also conditions of iron excess (such as haemochromatosis).