IGF-1 ELISA Assay Kit


The IGF-1 ELISA Assay Kit is an Enzyme-linked immunosorbent assay used for the quantitative and very sensitive determination of Insulin-like Growth Factor 1 (IGF-1) in serum and plasma.  The Human Insulin-like Growth Factor-1 (IGF-1) ELISA Assay kit is for research use only and should not be used in diagnostic procedures.

IGF-1 ELISA Assay Kit

The IGF-1 ELISA Assay Kit is For Research Use Only

Size: 1×96 wells
Sensitivity: 0.11 ng/mL
Dynamic Range: 2 – 50 ng/ml
Incubation Time: 1.75 hours
Sample Type: Serum, Plasma
Sample Size: 10 µL

Conversion Factor
ng/mL = nmol/L x 0.13
nmol/L = ng/mL x 7.65

Product is manufactured by Mediagnost

Assay Principle

In order to dissociate IGF-I from the IGFBPs, the samples must be diluted in an acidic buffer (Sample Buffer PP). The diluted samples are then pipetted into the assay wells. The IGF-I antiserum is dissolved in a buffer, which is able to neutralize the acidic samples. After the IGF-I antibody solution has neutralized the samples, the present excess IGF-II occupies the IGF-binding sites of the binding proteins, thus allowing the measurement of the resulting free IGF-I. With this method, the IGFBPs are not removed, but their function and therefore their interference in the assay is neutralized. Due to the extremely low cross-reactivity of the IGF-I antibody with IGF-II, the excess of IGF-II does not disturb the interaction of the first antibody with IGF-I.

The Eagle Biosciences  ELISA for IGF-I is a so-called Sandwich-Assay using two specific and high-affinity antibodies. The IGF-I in the samples binds to the first antibody coated on the microtiterplate, the second specific anti-IGF-I-antibody binds in turn to the immobilised IGF-I. The second antibody is biotinylated, the subsequently incubated Streptavidin-Peroxidase-Enzyme Conjugate will bind to it, and thus in the final substrate incubation step colour development will be catalysed quantitatively depending on the IGF-I-level of the samples. The Standards of this ELISA are prepared from recombinant IGF-I in concentrations of 2, 5, 15, 30 and 50 ng/ml.

The standards are derived from recombinant hIGF-I devoid of methIGF-I or IGF-I variants with mismatched disulfide bonds, i.e. this recombinant IGF-I is identical to the major authentic IGF-I form in blood. The Eagle Biosciences, Inc. IGF-I enzymeimmunoassay is calibrated against the International Reference Standard preparation of IGF-I, WHO NIBSC Code 02/254.

Related Products

Human IGFBP-1 ELISA Assay

Additional Information

Assay Background

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.

A major problem of IGF-I measurement results from the interference of IGFBPs in the assay. Direct determinations in untreated serum samples give false values because of the extremely slow dissociation of the IGF-I/IGFBP-3 complexes during the assay incubation. Depending on the ratio IGF-I to IGFBP the following errors may occur (see also Figure below):

Therefore, various techniques were applied to physically separate IGF-I from its binding proteins before measurement, including (a) size exclusion chromatography under acidic conditions, (b) solid-phase extraction and (c) acid-ethanol extraction. These techniques, however, are either inconvenient or time-consuming or give incomplete and not-reproducible recoveries. The most widely used method is the acid-ethanol extraction with a recovery of only 70-80 % of IGFBP-bound IGF-I as a result of co-precipitation. The absolute results of such an extraction are therefore falsely low . The extraction removes the IGFBPs only insufficiently and leads to reduction in sensitivity of the assay due to pre-dilution of the samples by the extraction procedure. Furthermore, the remaining IGFBP may still interfere in the assay. In addition, the acid-ethanol extraction is ineffective in specimens other than serum or plasma (e.g. cell culture media), in which determination of IGF-I is already difficult enough due to the fact that IGFBPs are frequently present at large excess.

To avoid these difficulties, an uncomplicated assay was developed, in which special sample preparation is not required before measurement.

Package Inserts

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