Evaluation of new immunoenzymometric assay for measuring soluble transferrin receptor to detect iron deficiency in anemic patients

Abstract

During the last few years the measurement of serum-soluble transferrin receptor (sTfR) has been introduced as a tool to detect iron deficiency and as an analyte to differentiate between anemia caused by iron deficiency (IDA) and that caused by chronic disease (ACD). Commercially available methods have emerged to make diagnostics by sTfR more readily accessible. We documented the analytical performance of a newly introduced IDeATM sTfR immunoenzymometric assay (IEMA) by Orion Diagnostica. We also evaluated its clinical performance in 98 consecutive anemic patients, with information derived from bone marrow aspirate samples as the reference for iron status. The clinical usefulness of two other commercially available sTfR assays was assessed for comparison. The analytical performance and clinical applicability of the IDeA were sufficient to support reliable clinical work. We conclude that IDA and iron deficiency in the presence of inflammatory states can be differentiated efficiently from ACD with this new commercial test to measure sTfR.

Erythropoietic activity and soluble transferrin receptor level in neonates and maternal blood

“…The number of transferrin receptors expressed on the cell surface reflects the iron requirements of a tissue (9, 23). Iron deprivation induces a prompt synthesis of the transferrin receptor (9). Increased blood sTfR values are usually observed in iron-depleted states, whereby the concentration of sTfR correlates inversely with the amount of iron available for erythropoiesis (24).…”

“…Serum transferrin receptor levels were determined by an immunoenzymometric method using IDeA 2 sTfR kits (Orion Diag-nostica, Orion Co., Finland). The sTfR test was performed as described previously (9). We diluted and reanalysed any sample that had a concentration higher than the highest calibrating standard.…”

“…The erythropoietic cells of bone marrow and the circulating reticulocytes eventually shed their transferrin receptors into the blood during their maturation sequence (8). Thus, the sTfR concentration correlates directly with erythropoietic activity and inversely with the amount of iron available for erythropoiesis (9). Increased sTfR concentrations are usually observed in iron deficiency, or in cases of iron depletion in tissues, although this index is not always specific for iron deficiency (10).…”

The reference limits and cut‐off value for serum soluble transferrin receptors for diagnosing iron deficiency in infants

“…Laboratory criteria for ID include a low MCV, a low concentration of serum ferritin and transferrin saturation (Mast et al, 1998). In recent years free erythrocyte protoporphyrin (FEP) and zinc protoporphyrin (ZPP), sTfR, sTfR/ferritin ratio and reticulocyte Hb content (CHr) have also been used to detect the onset of ID erythropoiesis (Hastka et al, 1996;Major et al, 1997;Suominen et al, 1997;Goodnough, Skikne & Brugnara, 2000;Ullrich et al, 2005;Angeles Vazquez Lopez et al, 2006).…”

Soluble transferrin receptor and zinc protoporphyrin – competitors or efficient partners?

“…It was shown that the sTfR-concentration depends on the erythropoietic activity as well as on iron metabolism. Elevated sTfR values were measured in patients suffering from hematological disorders with increased erythropoiesis like hemolytic anemia, thalassemia, spherocytosis, or polycythemia vera (8)(9)(10)(11)(12)(13)(14)(15)(16), but also in patients with ID (9,10,(17)(18)(19)(20)(21)(22)(23)(24)(25). In ID patients, the sTfR does not increase before IDE has developed.…”