How do you interpret a serum iron level of 39, with Total Iron Binding Capacity (TIBC) 265, percent transferrin saturation 15 and ferritin 113?

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From the Guidelines

These lab values suggest iron deficiency, and treatment should include oral iron supplementation to improve morbidity, mortality, and quality of life. The serum iron level of 39 is below the normal range (typically 60-170 μg/dL), while the TIBC of 265 is within normal limits (250-450 μg/dL) 1. The transferrin saturation of 15% is low (normal is 20-50%), indicating inadequate iron availability for red blood cell production, as supported by the formula for calculating transferrin saturation: Transferrin saturation (%) = {serum iron concentration (ug/dL)/TIBC (ug/dL)} x 100 1. Although the ferritin level of 113 is technically within normal range, it may be falsely elevated if there's underlying inflammation, and a cut-off of 45 μg/L has been suggested as providing the optimal trade-off between sensitivity and specificity for iron deficiency in practice 1. Treatment with oral iron supplementation, typically ferrous sulfate 325 mg taken 1-3 times daily between meals with vitamin C to enhance absorption, is recommended. Side effects may include constipation, nausea, and black stools. If oral iron isn't tolerated or effective, intravenous iron formulations like iron sucrose or ferric carboxymaltose may be needed, as suggested by guidelines for managing iron deficiency anaemia in adults 1. It's essential to investigate the cause of iron deficiency, which could include blood loss (menstruation, gastrointestinal bleeding), malabsorption, or dietary insufficiency, and follow-up testing in 2-3 months should show improvement in these parameters with successful treatment, ultimately improving patient outcomes in terms of morbidity, mortality, and quality of life. Key considerations in managing iron deficiency include distinguishing between absolute and functional iron deficiency, as well as recognizing the potential for inflammation to affect laboratory results, such as serum ferritin levels 1. By prioritizing the most recent and highest-quality evidence, we can ensure that patients receive the most effective treatment for iron deficiency, leading to improved health outcomes.

From the Research

Interpretation of Iron Level Results

The provided iron level results include:

  • Serum iron level: 39
  • Total Iron Binding Capacity (TIBC): 265
  • Percent transferrin saturation: 15
  • Ferritin: 113

Diagnosis of Iron Deficiency

According to the study 2, iron deficiency is diagnosed by low serum ferritin (typically <30 ng/mL) in individuals without inflammatory conditions or by transferrin saturation (iron/total iron binding capacity × 100) less than 20%. In this case, the ferritin level is 113, which is above the typical threshold for iron deficiency. However, the transferrin saturation is 15, which is below the threshold of 20%.

Transferrin Saturation and TIBC

The study 3 states that no single test is diagnostic of iron deficiency unless the serum ferritin is low or the percent transferrin saturation is low with an elevated total iron binding capacity. In this case, the TIBC is 265, which is elevated, and the transferrin saturation is low (15%). This suggests that the individual may have iron deficiency, despite the ferritin level being above the typical threshold.

Treatment Options

The study 2 recommends oral iron as first-line therapy for most patients with iron deficiency. However, the study 3 notes that intravenous iron is indicated for patients with oral iron intolerance, poor absorption, or certain chronic inflammatory conditions. The study 4 highlights the importance of updating guidelines for the management of iron deficiency anemia, including the use of intravenous iron.

Summary of Findings

In summary, the provided iron level results suggest that the individual may have iron deficiency, despite the ferritin level being above the typical threshold. The low transferrin saturation and elevated TIBC support this diagnosis. Treatment options, including oral and intravenous iron, should be considered based on the individual's specific needs and medical history, as recommended by studies 2, 3, and 4.

References

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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