Reticulocyte indices rapidly reflect an increase in iron availability for erythropoiesis.

An increase in blood hemoglobin content following iron supplementation can confirm a diagnosis of iron deficiency, but the long delay in response is a major drawback and makes this approach inappropriate for routine clinical use. We evaluated the ability of red blood cell and reticulocyte indices to reflect the increase in iron availability for erythropoiesis. We found that the reticulocyte hemoglobin content and, in particular, the percentage of hypochromic reticulocytes rapidly reflect the response of erythropoiesis to iron medication in iron-deficient subjects.