Transferrin Saturation Calculator

Calculate transferrin saturation from serum iron and total iron-binding capacity to help distinguish iron deficiency from iron overload states such as hereditary haemochromatosis.

🩸 Lab Value📐 TSAT (%) = (serum iron / TIBC) × 100🏥 Health
Serum iron (µg/dL)
TIBC (µg/dL)
Ferritin (ng/mL, optional)
Please enter valid values.

Formula & Reference

VariableSymbolFormulaUnits
Transferrin Saturation Calculator—TSAT (%) = (serum iron / TIBC) × 100percent

Step-by-Step Examples

Example 1
Normal Iron Status

Serum iron 90 µg/dL, TIBC 320 µg/dL, ferritin 80 ng/mL.

  • TSAT = (90 / 320) × 100
  • TSAT = 28.1%
  • Ferritin normal, consistent picture
✓ TSAT 28.1% — normal range
Example 2
Iron Deficiency

Serum iron 28 µg/dL, TIBC 450 µg/dL, ferritin 8 ng/mL.

  • TSAT = (28 / 450) × 100 = 6.2%
  • TIBC is elevated, a typical deficiency response
  • Low ferritin confirms depleted stores
✓ TSAT 6.2% — iron deficiency pattern
Example 3
Possible Iron Overload

Serum iron 210 µg/dL, TIBC 280 µg/dL, ferritin 890 ng/mL.

  • TSAT = (210 / 280) × 100 = 75%
  • TIBC is low, the opposite of the deficiency pattern
  • High ferritin alongside high TSAT warrants evaluation
✓ TSAT 75% — iron overload pattern

Real-World Applications

🩸
Haemochromatosis Screening
Transferrin saturation is the recommended first-line screening test for hereditary haemochromatosis, generally more sensitive early than ferritin alone.
💉
Anaemia Workup
Combining TSAT with ferritin helps separate iron deficiency anaemia from anaemia of chronic disease, which have very different treatments.
🏥
Dialysis Care
Iron status monitoring using TSAT and ferritin is routine in chronic kidney disease patients receiving erythropoiesis-stimulating agents.
📚
Haematology Education
The TSAT and ferritin combination is a standard teaching framework for interpreting disorders of iron metabolism.

Common Mistakes to Avoid

⚠️
Interpreting ferritin without inflammatory context

Ferritin is an acute phase reactant that rises with any inflammation, infection, liver disease, or malignancy. A normal ferritin does not exclude iron deficiency when inflammation is present.

⚠️
Ignoring diurnal and dietary variation

Serum iron fluctuates considerably through the day and after iron-containing meals or supplements. Morning fasting samples give the most consistent results.

⚠️
Diagnosing haemochromatosis on one elevated result

A single high transferrin saturation warrants repeat fasting testing and, if persistently elevated, genetic testing — not an immediate diagnosis.

Frequently Asked Questions

What is transferrin saturation? ▾
The percentage of transferrin's iron-binding sites actually carrying iron, calculated as serum iron divided by total iron-binding capacity.
What is a normal transferrin saturation? ▾
Roughly 16–45% in most laboratories, though exact reference ranges vary and men typically sit slightly higher than women.
What does a high transferrin saturation mean? ▾
Values above about 45% in men or women warrant evaluation for iron overload, most commonly hereditary haemochromatosis, particularly when ferritin is also elevated.
Why measure TSAT rather than just ferritin? ▾
Ferritin reflects storage iron but rises with inflammation, while transferrin saturation reflects iron actually available for transport — the two together give a far clearer picture.
Should I fast before an iron panel? ▾
Yes, morning fasting samples are preferred, since serum iron varies with the time of day and rises after iron-containing food or supplements.

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