Randox Reagents are continuing to develop their anaemia testing panel by introducing soluble transferrin receptor (sTfR). Iron deficiency is the most common nutritional deficiency in the world with around 15%-20% of the entire population suffering from iron deficiency anaemia (IDA). 1 Providing an extensive diagnostic tool box allows clinicians to obtain a clearer picture of a patient’s anaemia allowing them to pin down the type in order to provide efficient treatment. The addition of sTfR compliments the existing panel that Randox currently offers allowing the measurement of stored cellular iron.
Currently Randox offer a number of diagnostic reagents for use on a wide range of biochemistry analysers that have shown clinical utility in testing for anaemia including; iron, ferritin, transferrin, unsaturated iron binding capacity (UIBC) and total iron binding capacity (TIBC). Table 1 provides a description of the currentRandox anaemia testing panel.
|Table 1 : The current Randox Anaemia Testing Panel|
|Iron||Iron deficiency is one of the most prevalent human disorders resulting in deficient haem synthesis. The Randox iron assay allows clinicians to measure and assess a patient’s iron levels allowing them to treat iron deficiency anaemia, haemochromatosis and chronic renal disease.|
|Ferritin||Ferritin originates in the reticuloendothelial system consisting of a protein shell and contains varying amounts of iron in its core. Elevated levels of ferritin have been seen in anaemia associated with chronic disease and elevated levels have been noted in patients with chronic
|Transferrin||Transferrin is the principal iron binding and transport protein in human plasma. Iron availability in the plasma regulates transferrin levels which increase when plasma iron is low. Plasma transferrin levels are associated with a range of conditions including anaemia, iron deficiency,
inflammation or malignancy, liver disease, malnutrition and protein loss and have been known to
increase during pregnancy.
|UIBC||In the measurement of serum iron, ferric iron is dissociated from its carrier protein, transferrin, in an acid medium and simultaneously reduced to the ferrous form. When measuring UIBC, a known amount of ferrous iron is added to saturate the unoccupied iron binding sites on the transferrin. The amount of free iron present is measured and subtracted from the total amount
added to calculate the UIBC.
|TIBC||TIBC is the amount of iron needed to completely saturate transferrin. It has utility in monitoring iron deficiency anaemia in late pregnancy as levels are elevated when iron levels are low. In addition, abnormal levels of TIBC can also indicate liver disease, malnutrition and hereditary haemochromatosis.|
What is sTfR?
sTfR is a truncated form of the transferrin receptor formed as a result of proteolysis, a reaction that involves the breakdown of proteins into smaller polypeptides and amino acids. 1 Transferrin transports iron around the body and donates this through interacting with a specific membrane receptor known as the transferrin receptor (TfR). 2 sTfR has been found to be present in animal and human serum and circulating freely in the blood. The concentration of sTfR is directly proportional to the concentration of the membrane bound transferrin receptors. Figure 1 illustrates a comparison of sTfR and membrane bound transferrin receptors concentration and their directly proportional relationship.
Figure 1 : Directly proporational relationship between sTfR and membrane bound transferring receptors
Due to its presence in human serum, sTfR has been found to be a marker of iron status. In iron deficiency anaemia levels of sTfR are significantly increased, however it remains normal in acute phase conditions including chronic and inflammatory diseases. For this reason, sTfR has been found to have clinical utility in the differential diagnosis of anaemia including anaemia of chronic disease (ACD) and iron deficiency anaemia (IDA).
In IDA, increased sTfR levels have been observed in haemolytic anaemia, sickle cell anaemia, B12 deficiency and functional iron deficiency in pregnancy. In contrast, in ACD, sTfR levels do not correlate with iron status. This was observed in patients with chronic illnesses, certain infections, autoimmune diseases and inflammatory diseases. sTfR is a useful test where ferritin tests may be inconclusive. As ferritin is an acute phase reactant, levels will increase in response to inflammation. As sTfR is not an acute phase reactant, sTfR levels are not impacted by inflammation.
Key Benefits of the RandoxsTfR assay:
> Liquid ready-to-use reagent for convenience and ease-of-use
> Latex enhanced immunoturbidimetric method facilitating testing on biochemistry analysers and eliminating the need for dedicated equipment.
> Excellent measuring range of 0.5 – 11.77 mg/L, for the comfortable detection of clinically important results.
> Excellent correlation coefficient of r=0.977 when compared against other commercially available methods.
> Stable to expiry when stored at +2 to +8°C.
> Applications are available detailing instrument-specific settings for the convenient use of the RandoxsTfR assay on a wide range of biochemistry analysers.