This assay employs the quantitative sandwich enzyme immunoassay technique. An antibody specific for Human IGF-I has been pre-coated onto a microtiter plate. IGF-I in samples will be release by diluted with an acidic Sample/Standard diluent buffer from IGF1BPs. Diluted standards or samples are pipetted into the wells and any IGF-I present is bound by the immobilized antibody. Then a biotin-conjugated antibody specific for IGF-I is added to each well and incubate. Following a washing to remove unbound substances, streptavidin conjugated to Horseradish Peroxidase (HRP) is added to each microplate well and incubated. After washing away any unbound antibodyenzyme reagent, a substrate solution (TMB) is added to the wells and color develops in proportion to the amount of IGF-I bound in the initial step. The color development is stopped by the addition of acid and the intensity of thecolor is measured at a wavelength of 450nm ±2nm.The concentration of IGF-I in the sample is then determined by comparing the O.D of samples to the standard curve. Sample Types: urine. Range: 0.5 - 50 mg/l. Sensitivity: 0.17 mg/l. Time: 1.75 hours ? Insulin-like growth factors (IGF) I and II play a pivotal role in regulating the proliferation, differentiation and specific functions of many cell types. IGF-I is identical with somatomedin C (Sm-C) and has a molecular weight of 7649 Daltons. Its major regulators are growth hormone (GH) and nutrition, although its production in specific tissues is affected by a multitude of tropic hormones and other peptide growth factors. In contrast to many other peptide hormones, IGFs are avidly bound to specific binding proteins (IGFBP). the seven classes of IGFBPs which are known at present either bind IGF-I and IGF-II with similar affinities or show a preference for IGF-II.