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Analyte: Insulin-like Growth Factor-1
Specimen Type: Serum, Heparin Plasma
Optimum Volume: 0.5 mL
|1 day||1 year||1 year|
Reporting units: ng/mL
Biological or Clinical Significance:
Insulin-like growth factor I is a single polypeptide chain with three intramolecule disulfide bonds. It consists of 70 amino acid residues with a molecular mass of 7,649 daltons. It is structurally homologous to IGF-II and insulin. IGF-I circulates primarily in a high molecular weight tertiary complex with IGF-binding protein-3 (IGFBP-3) and acid-labile subunit. In humans, plasma IGF-I levels are barely detectable at birth, rise gradually during childhood, peak during mid-puberty until approximately 40 years of age, then decline gradually. In the diagnosis of growth disorders, measurements of IGF-I are a useful indicator of growth hormone (GH) secretion Measurement of IGF-I is also useful in assessing change of nutritional status.
Principle of Test Method:
The IGF-1 assay is an automated enzymic chemiluminescent method.