RESUMO
Hemodialysis patients on maintenance erythropoietin need an adequate supply of iron to optimize therapy and achieve and maintain target levels of hemoglobin. Evaluation of iron stores and early detection of iron deficiency are essential for management of erythropoiesis in chronic renal failure, but there is still no single biochemical or hematological parameter that is sensitive or specific enough to completely describe the distribution of iron in the body. Serum transferrin receptor (sTfR) is a marker of iron that is available for erythropoiesis. We selected 2 clinical cases in which hemodialysis patients were receiving maintenance erythropoietin. To suggest how sTfR can be used in its double diagnostic meaning according to the clinical context of the patient, sTfR was evaluated in one case as a marker of iron deficiency and in the other as a marker of erythropoiesis. The association of sTfR with hematological parameters of iron-deficient erythropoiesis (reticulocyte hemoglobin content, percentage of hypochromic erythrocytes, ratio of reticulocyte hemoglobin content to hemoglobin content) and parameters of stimulated erythropoiesis (absolute reticulocyte count, immature reticulocyte fraction) increases the accuracy of sTfR in its double diagnostic power.
