Key Features and Values
- Highly sensitive assay with low limit of blank
- Highly accurate assay with low variation in repeat testing ensuring accuracy for support of treatment monitoring
- Supported by a comprehensive panel of markers for complete diagnosis and treatment monitoring of GHD and acromegaly
The IGF-I ELISA is intended for the quantitative determination of Insulin-like growth factor-I (IGF-I) in human serum and is intended for laboratory uses only. Results are to be used in conjunction with other clinical and laboratory data to assist the clinician in the assessment of growth disorders.
Insulin-like growth factor-I (IGF-I) is a polypeptide of 70 amino acids (7650 Daltons), and is one of a number of related insulin-like growth factors present in the circulation. The molecule shows approximately 50% sequence homology with proinsulin and has a number of biological activities similar to insulin.
The peptide is growth hormone (GH) dependent to a high degree, but there is growing evidence of GH-independent secretion. IGF-I has numerous growth-promoting effects, including mitogenic effects and the promotion of cartilage sulphation.
It also mediates growth promoting actions of growth hormone on skeletal and other body tissues. Almost all (>95%) of serum IGF-I circulates bound to specific IGF binding proteins, of which six classes (IGFBP’s 1-6) are now recognised. IGFBP-3 is thought to be the major binding protein of IGF-I, forming a ternary complex of 140,000 Daltons with IGF-I and an acid labile sub-unit.
The measurement of serum IGF-I is of recognised value in children with growth disorders and in the diagnosis and monitoring of acromegaly. IGF-I concentrations change with age, nutritional status, body composition and growth hormone secretion. A single basal IGF-I determination is useful in the assessment of short stature in children and in nutritional support studies of acutely ill patients.
For the diagnosis of acromegaly, a single IGF-I determination is considered more reliable than a random GH determination.