Circulating serum transferrin receptor level was measured using mouse monoclonal antibody against transferrin receptor (Orion Diagnostica, Finland) in 126 patients with various disorders of erythropoiesis and the results were compared to those obtained form control group consisted of 30 healthy volunteers with normal iron stores. Serum transferrin receptor level was significantly elevated in patients with iron deficiency and in all patients with hyperplastic erythropoiesis (hereditary spherocytosis, immune hemolytic anemia, beta thalassemia, myelodysplasia). Measurement of circulating serum transferrin receptor level was a sensitive indicator of iron depletion as well as a helpful parameter in differential diagnosis between iron deficiency and anemia of chronic disease where circulating transferrin receptor level was not elevated. Index transferrin receptor/ferritin calculated as a ratio of circulating serum transferrin receptor level to log serum ferritin level was a more sensitive parameter than measurement of serum transferrin receptor not only for determination of patients with anemia of chronic disease, but also for discrimination of patients with elevated serum transferrin receptor level due to true iron deficiency from those with high serum transferrin receptor level caused by relative iron deficiency in hyperplastic erythropoiesis.

Keywords: Diagnosis, Differential; Ferritins /blood/; Hematologic Diseases /blood/; Humans; Myelodysplastic Syndromes /blood/; Receptors, Transferrin /blood/