About Iron % Saturation
Transferrin saturation (iron % saturation) is the percentage of transferrin binding sites currently occupied by iron — calculated by dividing serum iron by TIBC and multiplying by 100. A saturation below 20% with low ferritin confirms iron deficiency; a saturation above 45–50% raises concern for hereditary haemochromatosis, a common genetic condition causing iron overload that can damage the liver, heart, and joints if untreated. This marker is the recommended first-line screen for haemochromatosis.