How this calculator works
Transferrin saturation is serum iron divided by total iron-binding capacity. Both must use the same concentration unit. When only transferrin is available, the BIOLABO assay documentation uses 1.25 µg of iron capacity per mg of transferrin; the resulting TIBC is an estimate tied to that factor. Other laboratories may use another factor or a measured capacity. Calculated saturation above 100% is displayed without clamping and should prompt laboratory review. The result is an estimate for information only and is not medical advice.
Formula
TSAT (%) = 100 x iron / TIBC. Estimated TIBC (µg/dL) = 1.25 x transferrin (mg/dL). Iron (µg/dL) = iron (µmol/L) x 5.5845.
Worked example
Iron 100 µg/dL and TIBC 400 µg/dL give 25%. Transferrin 240 mg/dL implies capacity 300 µg/dL; iron 60 µg/dL then gives 20%.
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Frequently asked questions
Can I mix iron in µmol/L with TIBC in µg/dL?
Convert them to the same unit first. The unit selector applies to both iron and TIBC.
Is estimated TIBC identical to a measured test?
No. The factor is method dependent, and other proteins can bind iron.
Does this establish iron deficiency?
No. Saturation is interpreted with ferritin, inflammation, blood count and the clinical assessment.