Natural and recombinant phosphorylated and non-phosphorylated human free IGFBP-1. This assay does not detect IGFBP-1 in complex with IGF-I or IGF-II.
< 0.5% cross-reactivity observed with available related molecules.< 50% cross-species reactivity observed with species tested.
No significant interference observed with available related molecules.
The Quantikine Human Free IGFBP-1 Immunoassay is a 4.5 hour solid-phase ELISA designed to measure human free IGFBP-1 in cell culture supernates, cell lysates, serum, plasma, urine, and human milk. It contains NS0-expressed recombinant human IGFBP-1 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human IGFBP-1 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 free IGFBP-1.
Intra-Assay Precision (Precision within an assay) Three samples of known concentration were tested twenty times on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays) Three samples of known concentration were tested in twenty separate assays to assess inter-assay precision. Assays were performed by at least three technicians using two lots of components.
The recovery of human Free IGFBP-1 spiked to levels throughout the range of the assay in various matrices was evaluated.
Average % Recovery
Cell Culture Media (n=4)
Cell Lysates (n=4)
EDTA Plasma (n=4)
Heparin Plasma (n=4)
Human Milk (n=4)
To assess the linearity of the assay, samples containing and/or spiked with high concentrations of human Free IGFBP-1 were 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.