< 0.5% cross-reactivity observed with available related molecules.Cross-species reactivity not tested.
No significant interference observed with available related molecules.
The Quantikine Human sFas Immunoassay is a 4.5 hour solid phase ELISA designed to measure human sFas in cell culture supernates, serum, and plasma. It contains recombinant human Fas/Fc chimera expressed from NS0 cells and antibodies raised against the recombinant factor. This immunoassay has been shown to accurately quantitate the recombinant factor. Results obtained measuring natural human sFas showed dose-response curves that were parallel to the standard curves obtained using the recombinant Fas/Fc chimera. These results indicate that this kit can be used to determine relative mass values for natural human sFas.
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 Fas/Fc chimera spiked to three different levels throughout the range of the assay in various matrices was evaluated.
Average % Recovery
Cell Culture Media (n=4)
Citrate Plasma (n=5)
EDTA Plasma (n=5)
Heparin Plasma (n=5)
To assess the linearity of the assay, five samples containing or spiked with high concentrations of sFas or Fas/Fc chimera were diluted with 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.
Fas (Fibroblast-associated), also known as Apo-1, CD95, and TNFRSF6, was originally identified as a cell-surface protein that binds to monoclonal antibodies that are cytolytic for various human cell lines. Alternatively spliced cDNAs encoding multiple Fas isoforms, including a soluble form of Fas, have been identified. Fas is highly expressed in epithelial cells, hepatocyes, activated mature lymphocytes, virus-transformed lymphocytes and other tumor cells. Fas expression has also been detected in mouse thymus, liver, heart, lung, kidney and ovary.
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.
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 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.
R&D Systems personnel manually curate a database that contains references using R&D Systems products.
The data collected includes not only links to publications in PubMed,
but also provides information about sample types, species, and experimental conditions.