The Quantikine Human IGFBP-3 Immunoassay is a 4.5 hour solid-phase ELISA designed to measure human IGFBP-3 in cell culture supernates, serum, and plasma. It contains NS0-expressed recombinant human IGFBP-3 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human IGFBP-3 showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for naturally occurring human IGFBP-3.
Intra-Assay Precision (Precision within an assay) Three samples of known concentration were tested on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays) Three samples of known concentration were tested in separate assays to assess inter-assay precision.
The recovery of IGFBP-3 spiked to three different levels throughout the range of the assay was evaluated.
Average % Recovery
Cell Culture Media (n=4)
To assess the linearity of the assay, samples containing and/or spiked with high concentrations of IGFBP-3 were serially diluted with Calibrator Diluent to produce samples with values within the dynamic range of the assay.
Preparation and Storage
Store the unopened product at 2 - 8 °C. Do not use past expiration date.
The superfamily of insulin-like growth factor (IGF) binding proteins include the six high-affinity IGF binding proteins (IGFBP) and at least four additional low-affinity binding proteins referred to as IGFBP related proteins (IGFBP-rP). All IGFBP superfamily members are cysteine-rich proteins with conserved cysteine residues, which are clustered in the amino- and carboxy-terminal thirds of the molecule. IGFBPs modulate the biological activities of IGF proteins. Some IGFBPs may also have intrinsic bioactivity that is independent of their ability to bind IGF proteins. Post-translational modifications of IGFBP, including glycosylation, phosphorylation and proteolysis, have been shown to modify the affinities of the binding proteins to IGF. ALS (Acid Labile Subunit) is a liver-derived protein that exists in a ternary complex with Insulin-like Growth Factor (IGF)-binding Protein-3 (IGFBP-3) or IGFBP-5, and either IGF-I or IGF-II. ALS increases the half-life of IGF/IGFBP complexes in circulation.
Insulin-like Growth Factor Binding Protein 3
Entrez Gene IDs
3486 (Human); 16009 (Mouse);
acid stable subunit of the 140 K IGF complex; binding protein 29; binding protein 53; growth hormone-dependent binding protein; IBP-3; IBP3BP-53; IGF-binding protein 3; IGFBP3; IGFBP-3; insulin-like growth factor binding protein 3; insulin-like growth factor-binding protein 3;
Refer to the product for complete assay procedure.
The conjugate must remain at 2-8 °C until use. Bring all other reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.
Prepare all reagents, standard dilutions, and samples as directed in the product insert.
Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.
100 µL Assay Diluent
Add 100 µL of Assay Diluent to each well.
100 µL Standard, Control, or Sample
Add 100 µL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at 2-8 °C for 2 hours.
Aspirate each well and wash, repeating the process 3 times for a total of 4 washes.
200 µL cold Conjugate
Add 200 µL of cold Conjugate to each well. Cover with a new plate sealer, and incubate at 2-8 °C for 2 hours.
Aspirate and wash 4 times.
200 µL Substrate Solution
Add 200 µL Substrate Solution to each well. Incubate at room temperature for 30 minutes. PROTECT FROM LIGHT.
50 µL Stop Solution
Add 50 µL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.
R&D Systems personnel manually curate a database that contains references using R&D Systems products.
The data collected includes not only links to publications in PubMed,
but also provides information about sample types, species, and experimental conditions.