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Diagnosis of Iron Deficiency Anemia: Ferritin Levels and Differentiation from Other Microcytic Anemias

Hispanic female doctor in her 40s examining a blood sample under a microscope in a medical laboratory. On the table, there are labeled test tubes, one marked 'Ferritin.' In the background, a computer screen displays a graph comparing ferritin levels with other indicators of iron deficiency anemia, including complete blood count and low MCV. The setting is professional and educational, emphasizing the differentiation of microcytic anemias.

Dear colleagues, iron deficiency anemia is one of the most common forms of anemia, characterized by a deficiency of iron that affects red blood cell production. In this article, we will explore the diagnosis of iron deficiency anemia, focusing on the importance of ferritin levels and how to differentiate it from other microcytic anemias.

Diving Deeper into the Diagnosis

The diagnosis of iron deficiency anemia begins with a complete blood count, where a low MCV (mean corpuscular volume) indicates microcytosis. However, the most reliable marker is low ferritin, which reflects the body's iron stores. Serum ferritin is the first laboratory test recommended to evaluate microcytosis, and low levels suggest iron deficiency.

In cases where ferritin is inconclusive, other parameters such as total iron-binding capacity, transferrin saturation, and soluble transferrin receptor levels can be utilized. The latter is particularly useful in situations where inflammation may alter ferritin results, as described in a multicenter study highlighting the utility of the sTfR/log ferritin index to improve the detection of iron deficiency anemia.

Moreover, it is crucial to differentiate iron deficiency anemia from other microcytic anemias such as thalassemia and anemia of chronic disease. The evaluation of microcytosis suggests that, in adults, iron deficiency anemia is presumed to be caused by blood loss, with the gastrointestinal tract being the most common source.

Conclusions

Accurate diagnosis of iron deficiency anemia is essential for effective treatment. Low ferritin remains the most reliable marker, but in complex cases, a combination of several parameters may be necessary for a comprehensive evaluation. Differentiation from other microcytic anemias is fundamental to avoid misdiagnosis and ensure appropriate patient management. Ongoing research and the use of advanced diagnostic tools, such as the sTfR/log ferritin index, are vital for improving diagnostic accuracy.

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Created 4/1/2025