IGFBP-3 ELISA

Enzyme immunoassay for the quantitative measurement of IGFBP-3.

INTENDED USE:This enzyme immunoassay kit is suited for measuring IGFBP-3 in human serum, EDTA and Heparinplasma for diagnostic and scientific purposes.

GENERAL INFORMATION:Insulin-like growth factors (IGF)-I and -II are bound to specific binding proteins (IGFBPs) in the circulation. To date, at least six binding proteins can be distinguished on the basis of their amino acid sequence. They are designated as IGFBP-1, IGFBP-2, ... IGPBP-6. The predominating IGFBP in blood is IGFBP-3, which largely determines the total IGF-I and IGF-II concentration. In contrast to the other binding proteins, IGFBP-3 has the property to associate with an acid-labile subunit (ALS) after binding of either IGF-I or IGF-II. Most of the IGFBP-3 in plasma is present as high molecular weight ternary complex, however, small amounts of free IGFBP-3 are also found. The development of a specific immunoassays for IGFBP-3, which detects IGFBP-3 in the ternary complex, provided new in-sights into IGFP-3 regulation. On the basis of these findings serum IGFBP-3 has been proven to be an additional useful test in the repertoire of diagnostic tools for evaluation of growth disorders. Several factors besides GH influence IGFBP-3 levels: age including sexual development, nutrition, hypothyroidism, diabetes mellitus, liver function and kidney function. IGFBP-3 levels are decreased by malnutrition, although less than IGF-I, in hypothyroidism, in diabetes mellitus and in hepatic failure, but are increased in chronic renal failure. Measurement over 24 hours revealed no circadian rhythm. For clinical practice, the most important regulatory factor is GH. Single IGFBP-3 measurements correlate significantly with the logarithm of the integrated spontaneous GH secretion. In patients with GH deficiency, IGFBP-3 levels are subnormal and increase gradually to within the normal range after several days of GH administration. The slow response to GH and constant circadian levels during chronic daily application of GH suggest that IGFBP-3 reflects the GH secretory state over days.

KIT CHARACTERISTICS:
- Method: ELISA
- Tests: 96
- Incubation Time / Conditions: 1 h, 1 h (RT/shaker), 30 min (RT)
- Standard Range: 0.4 - 30 ng/ml
- Sensitivity analytical: 0.03 ng/ml
- Final Sample Volume: 50 µl
- Sample Type: serum, plasma
- Sample Pretreatment: dilution 1:505
- Isotope / Substrate: TMB 450 nm
- Internal Controls: 2
- Regulatory Status: CE