What is iron saturation?

This question is about Nutrition

Sarah Achleithner

Iron saturation measures the amount of iron that is present in the blood. Therefore, low iron saturation means that there is a low amount of iron in the blood, which may indicate an iron deficiency. 

What are normal iron saturation levels?

There are a few ways to measure normal iron saturation levels.

  • Total iron-binding capacity (TIBC). TIBC is a test that can indicate iron saturation levels. The normal range for TIBC is 250–450 mcg/dl, so a value higher than this range may indicate iron deficiency or low iron saturation [



  • Transferrin. Transferrin saturation is calculated as the ratio of iron to transferrin or iron to total iron-binding capacity, and may indicate iron saturation levels in the blood [


    ].  The normal range for transferrin is 204–360 mg/dL, so any amount higher than this indicates a low level of iron saturation [



  • Serum iron test. This test measures the level of iron in the blood. The normal range for serum iron is 70–175 mcg/dl for males and 50–170 mcg/dl for females [


    ]. Values below these reference ranges also indicate a low iron saturation.

vials of lap samples waiting to be tested


  1. Transferrin. University of Rochester Medical Center. (n.d.).



  2. Pfeiffer, C. M., & Looker, A. C. (2017). Laboratory methodologies for indicators of iron status: strengths, limitations, and analytical challenges. The American journal of clinical nutrition, 106(Suppl 6), 1606S–1614S.



  3. Ogun, A. S. (2022, November 16). Biochemistry, transferrin. StatPearls.


  4. Iron and total iron-binding capacity. University of Rochester Medical Center. (n.d.).