Since sTfR concentrations may reflect both rates of erythropoiesis as well as cellular iron needs, several combined measures following log transformation of sTfR and/or ferritin have been used as highly specific and sensitive measures of iron deficiency in particular, including sTfR/log10[ferritin], log10[sTfR]/log10[ferritin], and log10[sTfR/ferritin] [31]. Here, TFRC is linked to nutritional disorder.