Iron, TIBC, and Iron Sat %

On May 7, 2010, in Minerals, Tests, by Andrea

It seems people really have trouble understanding iron.  I get it — iron is confusing all to hell.  There’s lots of things that I look at when I am evaluating iron status.  I look at things from the CBC (HCT, HGB, MCH, MCHC, RDW), things from a Hemogram, things from the TIBC, and a Ferritin level.  Sometimes?  I even look at a protein score.  So yes, very, very confusing.

Ranges given are simply given as a point of reference from MY laboratory.  Your lab may use slightly different lab values.  Adapt as necessary.

Many labs consider this a fasting test – but not all.  At the very least, it is best drawn in the morning.


TIBC, or Total Iron Binding Capacity: a test that looks at the blood’s ability to bind iron to a protein called transferrin; transferrin is the blood plasma protein that binds to iron for delivery around the body;  a high transferrin level may indicate iron deficiency anemia;  TIBC is not the same as UIBC, or unsatruated iron binding capacity, which is calculated by subtracting the serum iron from the TIBC; liver diseases may distort results as transferrin is produced in liver; Range: 180-545 ug/dl  (Andrea’s note: You WANT to be midrange here.  High is not good.  Low is not good.)

Transferrin saturation: the ratio of serum iron and total iron binding capacity x 100; always a percentage; Range: 15-55%

Serum iron: test that measures amount of circulating iron that is bound to transferrin in the blood; Range: 28-182 ug/ml  (Andrea’s ideal range: no less than 80 regardless of sex.)

Iron deficient anemia typically shows a low serum iron, high transferrin and TIBC because the liver is pumping out extra transferrin to make extra use of what little iron is in the blood.  Sat % is typically low as there is too little iron.

However, there are varying levels of anemia, as well as different types.  Thus having all of the tests makes it easier to determine the whole picture.

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