The Role of Reticulocyte Hemoglobin Content for Diagnosis of Iron Deficiency and Iron Deficiency Anemia, and Monitoring of Iron Therapy: a Literature Review

The diagnosis of iron deficiency anemia is still complicated and most of the tests have drawbacks. Bone marrow examination, the gold standard for the diagnosis of iron deficiency and iron deficiency anemia, is a painful, invasive, and costly procedure. Other methods are also used to diagnose iron deficiency and iron deficiency anemia; soluble transferrin receptor, serum iron, serum ferritin, and transferrin saturation are most common biomarkers of iron status that are frequently affected by inflammation, chronic diseases, and in the normal aging process (except soluble transferrin receptor). All are less available compared to complete blood count with reticulocyte hemoglobin content (CHr). Reticulocytes have a normal life span of one or two days in the circulation. CHr is a good indication of iron availability and an early marker of iron deficient erythropoiesis which can be obtained readily using automated blood cell analyzers. Therefore, the main objective of the current review is to assess the role of CHr for diagnosis of iron deficiency, iron deficiency anemia, and monitoring of iron therapy.Studies published in English were searched using the National Library of Medicine, PubMed, and Google scholar databases.According to this review, CHr has a moderate sensitivity and specificity for diagnosing iron deficiency, and is less affected by inflammation than serum iron, transferrin saturation, and ferritin and is an early predictor of treatment response. It is used in screening of iron deficiency, diagnosis of iron deficiency anemia, and diagnosis of functional iron deficiency anemia in acute or chronic diseases or inflammation. CHr is also important in treatment monitoring. It is useful for early measurement of response to iron therapy, increasing within days of the initiation of iron therapy. It helps monitoring of intravenous iron supplementation, recombinant human erythropoie¬tin therapy, and oral iron therapy in hemodialysis and non-hemodialysis patients, and children.It is easy to analyze, less time consuming, and less expensive than bone iron examination and iron biochemical tests. However, there is no standardized cutoff point and different researchers use varying cutoff values which affects its accuracy in diagnosing iron deficiency and it should therefore be standardized. Moreover, since CHr can be affected with any conditions that cause iron restricted erythropoiesis, further analysis may be needed.