The usefulness of the serum transferrin receptor in detecting iron deficiency in the anemia of chronic disorders

Abstract

BACKGROUND AND OBJECTIVE: Recent studies have shown that the serum transferrin receptor (sTfR) is a sensitive, quantitative measurement of tissue iron deficiency. The objective of the study was to evaluate the diagnostic efficiency of some laboratory tests, including sTfR measurements, in the diagnosis of iron depletion in patients with anemia of chronic disorders. DESIGN AND METHODS: The patient population consisted of 37 anemic patients: 10 hypoferritinemic patients (serum ferritin < 25 micrograms/L), and 27 anemic in-patients with hyperferritinemia (serum ferritin > 200 micrograms/L) and clinical/analytical criteria of anemia of chronic disorders, who were submitted to a bone marrow aspirate with iron stain. The sensitivity and specificity of serum TfR was evaluated according to the results of bone marrow iron status. Statistical analysis employed Student's t-test, one way analysis of variance and a logistic regression model using the Wald test. RESULTS: Serum TfR was high in all the patients with hypoferritinemic anemia. In 12 patients with low bone marrow iron, the mean sTfR was 5.63 mg/L. In 6 of these 12 patients the sTfR was normal. On the other hand, sTfR was high in 4/15 patients with normal or increased iron stores. On multivariate analysis the most sensitive predictor of true iron deficiency was MCH (mean corpuscular hemoglobin). No other variables remained independently significant, including sTfR, after the inclusion of MCH in this model. INTERPRETATION AND CONCLUSIONS: In our opinion, the iron status of patients with anemia of chronic diseases can not be accurately assessed by sTfR, as its sensitivity and specificity are low. In these patients, the gold standard for iron stores evaluation continues to be bone marrow aspirate and Perls stain.