< 0.5% cross-reactivity observed with available related molecules.< 50% cross-species reactivity observed with species tested.
No significant interference observed with available related molecules.
The Quantikine Human FGF-21 Immunoassay is a 4.5 hour solid-phase ELISA designed to measure human FGF-21 in cell culture supernates, serum, and plasma. It contains E. coli-expressed recombinant human FGF-21 and has been shown to accurately quantitate the recombinant factor. Results obtained using natural human FGF-21 showed linear curves that were parallel to the standard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for naturally occurring human FGF-21.
Intra-Assay Precision (Precision within an assay) Three samples of known concentration were tested on one plate to assess intra-assay precision.
Inter-Assay Precision (Precision between assays) Three samples of known concentration were tested in separate assays to assess inter-assay precision.
The recovery of FGF-21 spiked to levels throughout the range of the assay in various matrices was evaluated.
Average % Recovery
Cell Culture Media (n=4)
EDTA Plasma (n=4)
Heparin Plasma (n=4)
To assess the linearity of the assay, samples spiked with high concentrations of FGF-21 were serially diluted with the Calibrator Diluent to produce samples with values within the dynamic range of the assay.
Preparation and Storage
Store the unopened product at 2 - 8 °C. Do not use past expiration date.
FGF-21 (Fibroblast Growth Factor 21) is a member of an FGF subfamily that also includes FGF-19 and FGF-23. FGF-19 subfamily members lack a heparin binding domain, enabling them to freely circulate as endocrine factors and diffuse within tissues. FGF-21 signals through Klotho beta in complex with FGF receptors. It regulates cellular metabolism including glucose uptake in adipocytes and cellular sensitivity to insulin. It is basally expressed in the pancreas, thymus, liver, and adipose tissue and is upregulated in liver, muscle, and fat in obesity and diabetes. FGF-21 also plays a role in cell survival and proliferation, mesenchymal stem cell differentiation, circadian rhythm, and controlling reproductive capacity.
Refer to the product for complete assay procedure.
Bring all reagents and samples to room temperature before use. It is recommended that all samples, standards, and controls be assayed in duplicate.
Prepare all reagents, standard dilutions, and samples as directed in the product insert.
Remove excess microplate strips from the plate frame, return them to the foil pouch containing the desiccant pack, and reseal.
100 µL Assay Diluent
Add 100 µL of Assay Diluent to each well.
50 µL Standard, Control, or Sample
Add 50 µL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at room temperature for 2 hours.
Aspirate each well and wash, repeating the process 3 times for a total of 4 washes.
200 µL Conjugate
Add 200 µL of Conjugate to each well. Cover with a new plate sealer, and incubate at room temperature for 2 hours.
Aspirate and wash 4 times.
200 µL Substrate Solution
Add 200 µL Substrate Solution to each well. Incubate at room temperature for 30 minutes. PROTECT FROM LIGHT.
50 µL Stop Solution
Add 50 µL of Stop Solution to each well. Read at 450 nm within 30 minutes. Set wavelength correction to 540 nm or 570 nm.
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The data collected includes not only links to publications in PubMed,
but also provides information about sample types, species, and experimental conditions.