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Iron Studies (Serum Iron, TIBC, Transferrin Saturation)

Iron studies give a complete picture of your body's iron status: going beyond a simple haemoglobin level to show exactly where in the iron pathway the problem lies.

Written and clinically reviewed by Suman Konda, PharmD, Clinical Pharmacist · Based on peer-reviewed sources · Editorial policy · Not medical advice

Last reviewed and updated: · How we check our content

What are Iron Studies?

Iron studies are a panel of blood tests that measure different aspects of how your body handles iron. The panel typically includes: Serum Iron (iron in the blood right now), TIBC (Total Iron Binding Capacity, the maximum amount of iron your blood can carry), Transferrin Saturation (% of TIBC that is actually carrying iron), and often Ferritin (iron stores). Together, these tests tell your doctor whether you have iron deficiency, iron overload, or anaemia of chronic disease.

Iron studies interpretation patternsTypical iron study patterns and the condition each suggests.Why iron tests are read as a patternNo single iron test is diagnostic on its ownSerum ironFerritinTIBCTransferrin sat.Iron deficiencyLowLowHighLowAnaemia of inflammationLowNormal / highLowLowIron deficiency + inflammationLowNormalNormalLowIron overloadHighHighLowHighNormal iron statusNormalNormalNormalNormalFerritin rises with inflammation, so a normal ferritin does not exclude iron deficiency when CRP is raised; transferrin saturation is less affected.
Scroll sideways to see the whole diagram
Iron study patterns and what each combination suggests.
What the table shows. Iron deficiency gives low iron, low ferritin, high TIBC and low transferrin saturation. Anaemia of inflammation looks similar on serum iron but ferritin is normal or high and TIBC is low, because ferritin is an acute-phase protein. The difficult case is the third row, iron deficiency occurring alongside inflammation, where ferritin can sit in the normal range while iron stores are genuinely depleted. That is why ferritin is interpreted next to CRP rather than alone.

Iron Studies Normal Range

TestNormal Range (Adults)
Serum Iron: Men65 – 175 µg/dL
Serum Iron: Women50 – 170 µg/dL
TIBC250 – 370 µg/dL
Transferrin Saturation20 – 50%
Ferritin: Men24 – 336 ng/mL
Ferritin: Women11 – 307 ng/mL

Iron Deficiency Pattern

LOW Iron deficiency anaemia pattern

Low serum iron + High TIBC + Low transferrin saturation (below 16%) + Low ferritin = Classic iron deficiency anaemia. Your body is starving for iron. TIBC is high because your blood is producing extra "carriers" desperately trying to grab any available iron. This pattern is the most common cause of anaemia worldwide, especially in women and children.

Anaemia of Chronic Disease Pattern

Anaemia of chronic disease (ACD) pattern

Low serum iron + Low TIBC + Low/Normal transferrin saturation + Normal or HIGH ferritin = Anaemia of chronic disease. This occurs in chronic infections (TB, HIV), autoimmune diseases, kidney disease and cancer. Iron is trapped inside cells and cannot be used, even though stores are adequate. Treating the underlying condition (not giving iron supplements) is the right approach here. Giving iron supplements in ACD is usually unhelpful and sometimes harmful.

Iron Overload Pattern

HIGH Iron overload (haemochromatosis) pattern

High serum iron + Low TIBC + High transferrin saturation (above 60%) + Very high ferritin = Iron overload. In hereditary haemochromatosis, the body absorbs too much iron and deposits it in organs (liver, heart, joints, pancreas). Treatment is regular blood donation (phlebotomy) to reduce iron. Very high transferrin saturation (above 45%) in otherwise healthy person should prompt a ferritin test and possibly genetic testing for HFE gene mutation.

Questions to ask your doctor

  • Is this iron deficiency anaemia or anaemia of chronic disease?
  • What is the underlying cause of my iron deficiency: diet, periods or gut bleeding?
  • Do I need IV iron or are tablets sufficient?
  • When should I recheck iron studies after starting treatment?

Frequently asked questions

Does the trend matter more than one Iron Studies reading?
For long-term monitoring it generally does. A figure that has drifted across several tests says more than a single measurement, and a stable result sitting slightly outside the range is often simply that person's baseline.
Do Iron Studies results from two different laboratories compare directly?
Not reliably. Methods differ, so a change between labs can reflect the assay rather than a change in you. Where Iron Studies is being tracked over time, staying with one laboratory makes the comparison meaningful.
Why did my Iron Studies change when nothing else did?
Biological variation is real. Hydration, time of day, recent food, exercise and a recent infection all move Iron Studies to some degree, and every assay carries its own small imprecision on top of that.

References

The clinical information on this page is drawn from peer-reviewed sources indexed by the US National Library of Medicine. Links go to the source so you can read it yourself.

  1. Iron-Binding Capacity. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK559119
  2. Biochemistry, Transferrin. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK532928
  3. Iron. In: StatPearls. Treasure Island (FL): StatPearls Publishing. NCBI Bookshelf NBK542171
  4. Masini G, Graham FJ, Pellicori P, et al. Criteria for iron deficiency in patients with heart failure. J Am Coll Cardiol. 2022;79(4):341-351. doi:10.1016/j.jacc.2021.11.039 · PMID 35086656

Related reading

Medical Disclaimer: This page is for general educational purposes only and does not constitute medical advice. Always consult a qualified doctor before making any health decisions.