CDSimple™ sTfR Chemiluminescent ELISA Kit

Sample

serum, slasma

Species Reactivity

Human

Detection Method

sELISA

Intended Use

The Quantitative Determination of sTfR Concentration in Human Serum or Plasma by a Microplate Enzyme Immunoassay, Colorimetric

Contents of Kit

A. sTfR Calibrators – 0.5 ml/vial
Six (6) vials of serum reference for sTfR at concentrations of 0 (A), 3.0 (B), 10 (C), 20 (D), 40 (E) and 80 (F) in nmol/L. A preservative has been added. Store at 2-8°C.
B. sTfR Enzyme Reagent – 12.0 ml/vial
One (1) vial of sTfR (Analog)-horseradish peroxides (HRP) conjugate in a protein-stabilizing matrix with red dye. Store at 2-8°C.
C. sTfR Biotin Reagent – 12.0 ml/vial
One (1) vial of reagent contains anti- sTfR biotinylated purified rabbit IgG conjugate in buffer, blue dye and preservative. Store at 2-8°C.
D. Streptavidin Coated Plate – 96 wells
One 96-well microplate coated with 1.0 μg/ml streptavidin and packaged in an aluminum bag with a drying agent. Store at 2-8°C.
E. Wash Solution Concentrate – 20.0 ml/vial
One (1) vial contains a surfactant in buffered saline. A preservative has been added. Store at 2-8°C.
F. Substrate Solution – 14.0 ml/vial
One (1) vial contains tetramethylbenzidine (TMB) and hydrogen peroxide (H₂O₂) in buffer. Store at 2-8°C.
G. Stop Solution – 8.0 ml/vial
One (1) vial contains a strong acid (0.5M H₂SO₄). Store at 2-8°C.
H. Product Instructions.
Note 1: Do not use reagents beyond the kit expiration date.
Note 2: Avoid extended exposure to heat and light. Opened reagents are stable for sixty (60) days when stored at 2-8°C. Kit and component stability are identified on label.
Note 3: Above reagents are for a single 96-well microplate.

Storage

2-8°C

Precision

The within and between assay precision of the sTfR ELISA Kit were determined by analyses on three different levels of pool control sera. The number, mean values, standard deviation and coefficient of variation for each of these control sera are presented in Tables.

Sensitivity

The sTfR ELISA Kit has a sensitivity of 0.055 nmol/L. The sensitivity was ascertained by determining the variability of the 0 nmol/L serum calibrator and using the 2σ (95% certainty) statistic to calculate the minimum dose.

General Description

The soluble transferrin receptor (sTfR) has been introduced as a promising new diagnostic tool for differentiating between iron deficiency anemia (IDA) and anemia of chronic disease (ACD). The circulating sTfR concentration is proportional to cellular expression of the membrane-associated TfR and increases with increased cellular iron needs and cellular proliferation. Furthermore, because serum ferritin reflects the storage iron compartment and sTfR reflects the functional iron compartment, the sTfR/log ferritin index (sTfR-F index), based on these two values, has been suggested as a good estimate of body iron compared with the sTfR/ferritin ratio. Distinguishing between IDA and ACD is a key step for determining whether iron supplementation would be beneficial.
As well as helping identify iron deficiency, sTfR is useful for monitoring erythropoiesis in malignancy and chronic renal disease. Development of erythropoiesis following bone marrow or stem cell transplantation is determined by the overall marrow proliferative capacity, which can be monitored with sTfR. During the aplastic period prior to transplantation, sTfR levels decline. Once erythropoiesis has recovered, sTfR levels return to normal values. In anemia of chronic renal failure, the early increase in sTfR values after starting recombinant human erythropoietin therapy is useful for predicting and assessing hematologic response to therapy. The change in sTfR levels occurs well before any change in hematocrit or hemoglobin values can be detected, allowing early adjustments in erythropoietin dosage and iron supplementation therapy.
sTfR and the sTfR/ferritin ratio also appear to have other useful applications. A recent study indicated that the sTfR/ferritin ratio can discriminate between anemic patients with and without coeliac disease. Subclinical iron deficiency in early pregnancy is strongly associated with bacterial vaginosis, and therefore sTfR and the sTfR/log ferritin index also might have a role in highlighting the risk of this condition. The sTfR/log ferritin index has also been shown to be superior to routine tests for predicting the response to iron therapy in long-term hemodialysis patients, and in discriminating between patients with iron deficiency and various hemoglobinopathies. Serum sTfR also reflects the rate of erythroid proliferation and iron demand, but as sTfR is not an acute phase reactant, it is unaffected by inflammatory process. sTfR is therefore a useful addition to the existing anemia assays.

Standard Curve