< 0.5% cross-reactivity observed with available related molecules.< 50% cross-species reactivity observed with species tested.
Interference observed with 1 or more available related molecules.
The Quantikine Human Follistatin Immunoassay is a 5.5 hour solid-phase ELISA designed to measure human Follistatin (FS288, FS300, and FS315) in follicular fluid, cell culture supernates, serum, and plasma. It contains Sf 21-expressed recombinant human Follistatin and antibodies raised against the recombinant factor. It has been shown to accurately quantitate recombinant human Follistatin. Results obtained using natural Follistatin 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 natural Follistatin.
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.
Cell Culture Supernates
Serum, EDTA Plasma, Follicular Fluid
The recovery of Follistatin spiked to three different levels in samples throughout the range of the assay in various matrices was evaluated.
Average % Recovery
Cell Culture Media (n=4)
EDTA Plasma (n=5)
To assess the linearity of the assay, samples containing and/or spiked with high concentrations of Follistatin were diluted with the appropriate 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.
Follistatin (FST) is a secreted glycoprotein that binds and neutralizes several TGF-beta superfamily proteins including Activin, BMP-6, BMP-7, and GDF-8/Myostatin. It also binds Angiogenin and regulates hematopoietic stem cell adhesion to Fibronectin. Some Follistatin binding partners will also bind Follistatin-like proteins such as FSL-3. Of three follistatin isoforms, the full-length mature follistatin (FST315) is the most abundant and the sole form in plasma, but has lower binding affinity for both activins and heparins than alternative forms. The acidic tail is missing in the splice variant FST288, which shows highest affinity, and partial in the proteolytically produced FST303, which shows intermediate affinity. Genetic deletion of follistatin in mice, or expression of only the FST288 form, is lethal perinatally due to defects of lung, skin and musculoskeletal system. Expression of only the FST315 isoform allows survival, with defects in vascularization and female fertility.
Refer to the product for complete assay procedure.
The conjugate must remain at 2-8 °C until use. Bring all other 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.
100 µL Standard, Control, or Sample
Add 100 µL of Standard, control, or sample to each well. Cover with a plate sealer, and incubate at 2-8 °C for 3 hours.
Aspirate each well and wash, repeating the process 3 times for a total of 4 washes.
200 µL cold Conjugate
Add 200 µL of cold Conjugate to each well. Cover with a new plate sealer, and incubate at 2-8 °C for 2 hours.
Aspirate and wash 4 times.
200 µL Substrate Solution
Add 200 µL Substrate Solution to each well.
For Cell Culture Supernate Samples: Incubate at room temperature for 20 minutes. PROTECT FROM LIGHT. For Serum, Plasma, & Follicular Fluid Samples: 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.