Medizinische Klinik III, Zentrum der Inneren Medizin der J.W. Goethe-Universität, Frankfurt am Main, Germany

Correspondence: Dr. Joachim P. Kaltwasser, Medizinische Klinik III, Zentrum der Inneren Medizin, J.W. Goethe-Universität, Theodor Stern Kai 7, D-60590 Frankfurt am Main, Germany. E-mail: kaltwasser@em.uni-frankfurt.de

Abstract

Erythropoietin and iron. Serum ferritin concentration is most informative in estimating the amount of storage iron available for a particular individual. The serum transferrin receptor concentration, in contrast to serum ferritin, provides direct information about any deficit in the adequacy of iron supply to the erythropoiesis. The combination of serum transferrin receptor and serum ferritin provides complete information about storage and functional iron compartments. Using this combination along with the hemoglobin concentration, it is possible to define the iron nutritional status completely. Inflammatory conditions as well as parenteral iron administration interfere, however, with the direct and quantitative ferritin to storage iron relationship and, therefore, have to be considered carefully with respect to diagnostic purposes. The diagnostic use of the serum transferrin receptor is presently limited because of limitations in methodology and definition (standardization) of reference ranges.