Iron Saturation Range and Interpretation

Standard Reference Values

The normal range for transferrin saturation (TSAT) is 20-50% in adults, according to the American College of Physicians 1
Low TSAT: <20% indicates iron deficiency or iron-deficient erythropoiesis in the general population, as suggested by the American Journal of Kidney Diseases and the American Journal of Hematology 2, 3
High TSAT: >50% suggests iron overload or iron-replete status, as indicated by the American Journal of Hematology 3, 4

In patients with chronic kidney disease, the target TSAT is ≥20% to support adequate erythropoiesis, as recommended by the National Kidney Foundation and the American College of Physicians 2, 5
In cancer patients, TSAT <20% with ferritin <30 ng/mL defines absolute iron deficiency, while TSAT 20-50% with ferritin 30-800 ng/mL defines functional iron deficiency, as defined by the American Journal of Hematology 3, 4

TSAT must be interpreted alongside other iron parameters, such as ferritin and hemoglobin, rather than in isolation, as emphasized by the American College of Physicians 1, 6
TSAT <20% alone does not mandate treatment unless accompanied by low ferritin or anemia, as suggested by the American College of Physicians 1, 6
Inflammation falsely lowers TSAT while elevating ferritin, making TSAT a more reliable indicator of iron availability in inflammatory conditions, as noted by the American College of Physicians 5
TSAT >20% does not exclude functional iron deficiency in patients receiving erythropoiesis-stimulating agents, as indicated by the American Journal of Kidney Diseases 2