Overview

Transferrin Saturation (TSAT) measures the percentage of transferrin (an iron-binding protein in blood) that is saturated with iron.
It helps evaluate iron status, especially iron deficiency or iron overload disorders.
TSAT is calculated using:
TSAT (%) = (Serum Iron / Total Iron-Binding Capacity) × 100

Risk Assessment / Clinical Use

TSAT is used to assess:

• Iron deficiency anemia

• Chronic disease anemia

• Iron overload disorders (e.g., Hemochromatosis)

• Response to iron therapy

• Monitoring patients with CKD on erythropoietin therapy

• Distinguishing between true iron deficiency and functional iron deficiency

Normal Reference Range

• 20–50% (may slightly vary by lab)

• Some labs use:

  • Male: 20–50%

  • Female: 15–50%

Interpretation

Low TSAT (<20%)

• Iron deficiency

• Chronic inflammation / chronic disease anemia

• CKD-related anemia

• Pregnancy

• Blood loss

Normal TSAT (20–50%)

• Normal iron status

High TSAT (>50%)

• Hemochromatosis (genetic or secondary)

• Excess iron intake or repeated transfusion

• Liver disease

• Hemolysis

Sample Type

• • Serum (blood sample)

  • Fasting is often preferred for accurate iron levels (morning sample).