Transferrin Saturation
Provide serum iron and total iron-binding capacity (TIBC) to compute transferrin saturation, an indicator of circulating iron availability.
Transferrin saturation
17.2%
How to Use This Calculator
Collect iron studies
Use serum iron and TIBC from the same blood sample. Select the units supplied by the laboratory (µg/dL or µmol/L).
Enter values accurately
Input the reported numbers. The calculator handles necessary unit conversions automatically.
Interpret TSAT with ferritin
Combine transferrin saturation with ferritin to differentiate iron deficiency, anemia of chronic disease, or iron overload disorders.
Formula
TSAT (%) = (Serum iron ÷ TIBC) × 100
Convert µmol/L values to µg/dL before applying the formula (1 µmol/L ≈ 5.585 µg/dL).
Full Description
Transferrin saturation reflects the percentage of transferrin binding sites occupied by iron. Low TSAT indicates insufficient available iron for erythropoiesis, while high TSAT suggests iron overload. Because TSAT fluctuates with diurnal variation and inflammation, interpret values alongside ferritin, CRP, and clinical context.
Frequently Asked Questions
What is the normal TSAT range?
Typical adult reference range is 20–50%. Values below 20% indicate iron-restricted erythropoiesis; above 50% raise concern for overload.
How does inflammation affect TSAT?
Inflammation lowers serum iron and elevates ferritin, reducing TSAT even when total body iron is adequate. Check CRP if results are discordant.
Should specimens be fasting?
Ideally yes, as recent oral iron intake transiently increases serum iron and TSAT.
Can TSAT be used to monitor IV iron therapy?
Yes. Measure TSAT and ferritin 1–2 weeks after infusion to assess iron repletion and avoid excessive iron loading.