The transferrin receptor (TfR) is the gateway for transferrin-bound-iron entering all body cells and soluble transferrin receptor (sTfR) is a proteolytic product of TfR that circulates in plasma. The two are directly proportional to each other. sTfR is proportional to erythroid precursor mass (i.e., rate of erythropoiesis), and is elevated in iron deficiency, when cells must be more competitive for obtaining their iron requirement.

Because other iron tests are affected by inflammation and in such cases do not measure deficiency accurately (Ferritin declines), sTfR provides the most reliable measurement of Iron Deficiency Anemia (IDA) and Anemia of Chronic Disease (ACD) marked by chronic inflammation with or without iron deficiency.
sTfR is also important in monitoring bone marrow or stem cell transplants for chronic renal disease. Monobind’s open-system AccuBind® ELISA and AccuLite® CLIA sTfR is suitable for manual and automated testing, with a short assay time of 1.5 hours, and based on streptavidin-biotin technology in a 96-well microplate, providing robust, accurate and reproducible results which strongly correlate with leading automated systems.