Low iron saturation (low transferrin saturation) means less circulating iron is bound and available for red blood cell production. It commonly reflects iron deficiency from blood loss, poor intake, or malabsorption, and can progress to iron-deficiency anemia. Further testing (ferritin, CBC) helps identify the cause; treatment may include dietary changes and iron supplementation under medical supervision.

Confirm low iron saturation with blood tests (including ferritin) and identify the cause (bleeding, poor diet, malabsorption). Increase iron intake: eat heme sources (red meat, poultry, fish) and fortified foods; pair nonheme iron with vitamin C and avoid tea/coffee or calcium around meals. Start oral iron supplements as directed by your clinician; consider IV iron if severe. Repeat labs and treat underlying causes.

Calculate transferrin (iron) saturation by dividing serum iron by total iron‑binding capacity (TIBC) and multiplying by 100: TSAT (%) = (serum iron ÷ TIBC) × 100. Use the same units for both (µg/dL or µmol/L). Typical reference range is about 20–50%; values <20% suggest iron deficiency, while >50% suggest iron overload. Interpret with clinical context and other lab tests.

Normal transferrin (iron) saturation is generally about 20–50% in adults (some labs use 15–50%). Values below ~15–20% suggest iron deficiency; values above ~50% suggest iron overload and may prompt evaluation for conditions such as hemochromatosis. Reference ranges vary by lab and method, so discuss abnormal results with your clinician for context and follow‑up testing.

Dangerously low iron is often indicated by serum ferritin below about 15 µg/L (15 ng/mL), reflecting depleted iron stores. Clinically significant anemia is usually present when hemoglobin falls below about 8 g/dL (severe anemia), causing fatigue, breathlessness, dizziness, palpitations, and increased cardiac strain. If you suspect very low iron or severe anemia, seek prompt medical evaluation and treatment.

Low transferrin saturation is commonly seen with cancers that cause chronic blood loss or inflammation. Gastrointestinal tumors (colorectal, stomach, esophageal) and gynecologic malignancies (endometrial, cervical, ovarian) often lead to iron deficiency. Genitourinary cancers with bleeding (bladder, renal) can also lower iron. Hematologic malignancies and many solid tumors cause inflammation, producing functional iron deficiency by hepcidin-mediated iron sequestration.