From the Guidelines
Low serum iron and transferrin levels together typically indicate iron deficiency anemia with depleted iron stores, as evidenced by a transferrin saturation level below 16% and serum ferritin level < 30 mcg/L in the absence of inflammation 1. When considering the implications of low serum iron and transferrin levels, it's crucial to understand that these indicators point towards a state where the body lacks sufficient iron to produce healthy red blood cells, and also has reduced transferrin, the protein responsible for transporting iron in the bloodstream.
Key Points to Consider:
- The combination of low iron, low ferritin, and low transferrin saturation (TfS) with increased transferrin receptor concentrations (sTfR) is indicative of isolated iron deficiency in the absence of inflammation 1.
- In the presence of biochemical evidence of inflammation, a serum ferritin level < 100 μg/L and TfS < 16% may indicate hypoferraemia, suggesting iron deficiency anemia (IDA) or anaemia of chronic disease (ACD) 1.
- The determination of sTfR can help differentiate between iron deficiency and ACD, as sTfR is high in iron deficiency and normal or low in ACD 1.
Clinical Implications:
The presence of low serum iron and transferrin levels necessitates a comprehensive evaluation to determine the underlying cause, which could include chronic blood loss, reduced iron intake or absorption, or the anaemia of chronic disease (ACD) 1.
Management:
Treatment typically involves iron supplementation, such as ferrous sulfate 325mg taken once or twice daily between meals with vitamin C to enhance absorption, for a duration of 3-6 months to replenish iron stores 1. Additionally, increasing iron-rich foods in the diet, including red meat, spinach, beans, and fortified cereals, is recommended. It is essential to consult a healthcare provider promptly if these lab results are indicated, as they could signify underlying issues such as chronic blood loss, malnutrition, or malabsorption that require further investigation beyond simple supplementation 1.
From the Research
Low Serum Iron and Transferrin Levels
- Low serum iron and transferrin levels can indicate iron deficiency anemia, which is the most common cause of microcytic anemia worldwide 2.
- Transferrin is an iron-binding protein that delivers iron to target tissues, and its deficiency can lead to anemia and oxidative stress 3.
- Serum transferrin receptor levels can be used to diagnose iron deficiency anemia, especially in patients with chronic diseases where ferritin levels may be increased 2.
- Low transferrin saturation levels can also indicate iron deficiency anemia, and are often used in combination with ferritin levels to diagnose the condition 4.
Diagnosis and Treatment
- The diagnosis of iron deficiency anemia can be complicated, and various tests have their drawbacks, including bone marrow examination, serum iron, serum ferritin, and transferrin saturation 5.
- Reticulocyte hemoglobin content (CHr) is a useful marker for diagnosing iron deficiency and iron deficiency anemia, and is less affected by inflammation than other tests 5.
- Treatment of iron deficiency anemia typically involves oral iron salts, but high-dose intravenous iron compounds are becoming increasingly popular, especially in patients with inflammatory disorders 4.
- Transferrin supplementation may also be beneficial in correcting anemia and reducing oxidative stress in patients with transferrin deficiency or iron overload 3.
Predictors of Response to Treatment
- Baseline iron and inflammation markers, such as reticulocyte hemoglobin content, transferrin saturation, and C-reactive protein, can predict the response to treatment in anemic hemodialysis patients with high serum ferritin and low transferrin saturation 6.
- However, the influence of these markers on the response to treatment is not always clinically significant, and further research is needed to identify reliable predictors of response to treatment 6.