What does a transferrin saturation (TSAT) percentage of 18%, Total Iron-Binding Capacity (TIBC) of 343, iron level of 63, and ferritin level of 20.8 indicate in a patient with iron deficiency anemia?

From the Guidelines

The laboratory values provided strongly indicate iron deficiency anemia, and treatment should include oral iron supplementation to replenish iron stores and improve quality of life. The patient's transferrin saturation (TSAT) of 18%, iron level of 63, TIBC of 343, and particularly the low ferritin of 20.8 ng/mL confirm iron deficiency as the cause of anemia, as a serum ferritin level < 30 mcg/L or transferrin saturation < 16% define iron deficiency in patients without evidence of inflammation 1. Key points to consider in the diagnosis and management of iron deficiency anemia include:

• The distinction between absolute and functional iron deficiency, with absolute iron deficiency defined as serum ferritin levels < 100 ng/mL and TSAT levels < 20% in CKD patients 1
• The use of serum ferritin and TSAT to diagnose iron deficiency, with a serum ferritin < 30 mg/L indicating iron deficiency in patients without clinical, endoscopic, or biochemical evidence of active disease 1
• The recommendation for iron supplementation in all IBD patients with iron-deficiency anemia, with intravenous iron demonstrating higher efficacy and better tolerance than oral iron in some cases 1
• The importance of investigating the underlying cause of iron deficiency, particularly focusing on potential sources of blood loss such as gastrointestinal bleeding or heavy menstrual periods. Treatment with oral iron supplementation, such as ferrous sulfate 325 mg taken 1-2 times daily between meals with vitamin C to enhance absorption, should continue for 3-6 months to replenish iron stores even after hemoglobin normalizes. If oral therapy is not tolerated or effective, intravenous iron formulations may be necessary, with the estimation of iron need usually based on baseline haemoglobin and body weight 1.

From the Research

Understanding Transferrin Saturation and Iron Deficiency Anemia

• Transferrin saturation (TSAT) percentage is a measure used to assess iron deficiency anemia, calculated by dividing the serum iron level by the total iron-binding capacity (TIBC) and multiplying by 100.
• A TSAT percentage of 18% indicates that 18% of the transferrin is saturated with iron, which is below the normal range, suggesting iron deficiency anemia 2.
• The given results: TSAT 18%, TIBC 343, iron 63, and ferritin 20.8, are indicative of iron deficiency anemia, as the TSAT is below 20% and the ferritin level is low 2.
• According to the study by 2, absolute iron deficiency is defined when the TSAT is ≤20% and the serum ferritin concentration is ≤100 ng/mL, which is consistent with the given results.
• The TIBC level of 343 is elevated, which is a common finding in iron deficiency anemia, as the body increases the production of transferrin to bind to the limited available iron 3.
• The ferritin level of 20.8 is low, indicating depleted iron stores, which is a key characteristic of iron deficiency anemia 4, 5.
• The diagnosis of iron deficiency anemia is typically based on a combination of laboratory tests, including serum ferritin, TSAT, and TIBC, as well as clinical evaluation 5, 6.

Clinical Implications

• Iron deficiency anemia can have significant clinical implications, including increased risk of morbidity and mortality, particularly in patients with chronic diseases such as chronic kidney disease 2.
• Treatment of iron deficiency anemia typically involves iron supplementation, which can be administered orally or intravenously, depending on the severity of the deficiency and the patient's underlying medical conditions 4, 2.
• It is essential to identify and address the underlying cause of iron deficiency anemia, as it may be a symptom of an underlying disease or condition, such as blood loss, increased demand, or disorders affecting iron absorption 4.