From the Guidelines
Low percent saturation on an iron panel indicates iron deficiency, with values below 20% generally indicating inadequate iron stores to fully saturate the available transferrin. This finding often appears before anemia develops and may be accompanied by low serum iron levels and elevated total iron binding capacity (TIBC) 1.
Key Points to Consider
- Normal transferrin saturation ranges from 20-50%
- A TSAT <20% has high sensitivity for diagnosing absolute or functional iron deficiency, but a ferritin of <100 ng/mL has a low sensitivity of 35%–48% 1
- Iron deficiency can result from inadequate dietary intake, poor absorption, or blood loss
- If you have low percent saturation, your healthcare provider may recommend iron supplementation and investigation of the underlying cause, such as gastrointestinal bleeding or malabsorption disorders
Diagnosis and Management
- Laboratory evaluation following IV iron should include a CBC and iron parameters (ferritin, percent transferrin saturation (TSAT) calculated by dividing the serum iron by the total iron binding capacity (TIBC)) 4 to 8 weeks after the last infusion 1
- Hemoglobin concentrations should increase within 1–2 weeks of treatment and should increase by 1 to 2 g/dL within 4–8 weeks of therapy
- Soluble transferrin receptor (sTfR) has been shown to be more sensitive in patients with inflammatory conditions where the ferritin (but not the TSAT) is unreliable for evaluation of ID and IDA 1
- Reticulocyte Hb content is a direct assessment of the functional availability of iron to the erythropoietic tissue and can be measured by two methods, the reticulocyte hemoglobin content (CHr) or reticulocyte hemoglobin equivalent (RET-He) 1
From the FDA Drug Label
Baseline serum transferrin saturation was 20% in the low-dose group, 16% in the high-dose group, and 14% in the historical control. Transferrin saturation <20% and/or serum ferritin <100 ng/mL
Low percent saturation on an iron panel refers to a transferrin saturation (TSAT) level below 20%. This indicates that the body's iron stores are depleted, and there is not enough iron available to meet the body's needs.
- A low TSAT level can be a sign of iron deficiency, which can lead to anemia and other health problems.
- In the context of the provided drug labels, a TSAT level below 20% is considered an indication for iron supplementation, such as with ferric gluconate (IV) 2.
From the Research
Iron Panel Results
- Low percent saturation on an iron panel refers to a low transferrin saturation (TSAT) level, which is calculated by dividing the serum iron level by the total iron binding capacity (TIBC) and multiplying by 100 3.
- A low TSAT level, typically less than 20%, indicates iron deficiency, which can be caused by various factors such as bleeding, impaired iron absorption, inadequate dietary iron intake, and pregnancy 3.
- Iron deficiency can progress to iron-deficiency anemia, characterized by low hemoglobin levels, and can cause symptoms such as fatigue, irritability, depression, and difficulty concentrating 3.
Diagnosis and Treatment
- Iron deficiency is diagnosed by low serum ferritin levels (typically <30 ng/mL) in individuals without inflammatory conditions or by TSAT less than 20% 3.
- Oral iron supplementation, such as ferrous sulfate, is typically the first-line therapy for iron deficiency, while intravenous iron is indicated for patients with oral iron intolerance, poor absorption, or certain chronic inflammatory conditions 3, 4.
- Studies have compared the efficacy of different iron supplements, such as ferric citrate and lactoferrin, in treating iron deficiency, with varying results 4, 5.
Related Studies
- A study published in 2020 found that ferric citrate resulted in a greater increase in TSAT and ferritin levels compared to ferrous sulfate in patients with moderate to severe chronic kidney disease and iron deficiency 4.
- Another study published in 2022 found that lactoferrin supplementation had better effects on serum iron, ferritin, and hemoglobin levels compared to ferrous sulfate, but had a reducing effect on fractional iron absorption 5.