| sTfR

Soluble transferrin receptors usually refer to the cleaved extracellular part of transferrin receptor 1 released into the serum. This receptor is a protein dimer of two identical subunits, linked together by two pairs of disulfide bonds. Its molecular weight is 190,000 Daltons. Its blood test is used to measure functional iron status and research on iron deficiency anemia. Ferritin is a routine test for anemia and is an acute phase reactant. It may increase in an inflammatory state, thereby wrongly indicating an adequate iron reserve. Because sTfR is insensitive to inflammation, it can be used to detect anemia in patients with a previous inflammatory state, and is particularly useful in differentiating anemia caused by chronic diseases from that caused by iron deficiency. To date, the routinely identified soluble transferrin receptors themselves have no relation to the intracellular delivery of transferrin and the related iron storage.
 

| Typical data

As the OD values of the standard curve may vary according to the conditions of the actual assay performance (e.g. operator, pipetting technique, wash technique or temperature effects), the operator should establish a standard curve for each test. Typical standard curve and data are provided below for reference only.

 

Concentration (ng/mL)	100	50	25	12.5	6.25	3.12	1.56	0
OD	2.52	1.96	1.38	0.97	0.55	0.31	0.19	0.08
Corrected OD	2.44	1.88	1.3	0.89	0.47	0.23	0.11	-

 

| Repeatability

Intra-assay Precision (Precision within an assay)：CV% < 10%; Inter-assay Precision (Precision between assays)：CV% < 10%
 

| Recovery

The recovery of Human sTfR spiked at three different levels in samples throughout the range of the assay was evaluated in various matrices.

 

Sample Type	Range(%)	Average Recovery(%)
Serum(n=8)	81-101	95

 

| Linearity

Samples were spiked with high concentrations of Human sTfR and diluted with Universal Diluent to produce samples with values within the range of the assay.

 

		Serum(n=4)
1 : 2	Range (%)	82-95
	Average (%)	91
1 : 4	Range (%)	89-103
	Average (%)	96