Bio-Rad Bio-Plex Pro™ Rat Cytokine, Chemokine, and Growth Factor Assays - Manual (Page 19)

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2. For serum, allow blood to clot at room temperature for 30 to 45 min.
For plasma, proceed directly to the centrifugation steps.
3. Perform centrifugation at 1,000 x g for 15 min at 4°C and transfer the
serum or plasma to a clean polypropylene tube.
4. To completely remove platelets and precipitates, centrifuge again at
10,000 x g for 10 min at 4°C.
5. Dilute samples fourfold (1:4) by adding 1 volume of sample to 3
volumes of Bio-Plex sample diluent (for example, 40 µl sample
+ 120 µl sample diluent).
6. Assay samples immediately or aliquot into single-use tubes and store
at –70°C. Avoid repeated freeze-thaw cycles.
Cell Culture Supernatant
1. Collect supernatants and centrifuge at 1,000 x g for 15 min at 4°C.
For cell lines cultured in serum-free culture media, collect samples and
add BSA as a carrier protein to a final concentration of at least 0.5% to
stabilize protein analytes and to prevent adsorption to labware.
2. Transfer to a clean polypropylene tube. If cellular debris or precipitates
are present, centrifuge again at 10,000 x g for 10 min at 4°C.
3. We recommend testing undiluted samples first. If levels are
anticipated to be high, samples can be further diluted in culture
medium. Rarely would samples need to be diluted greater than 1:10.
4. Assay immediately or store samples in single-use aliquots at –70°C.
Avoid repeated freeze-thaw cycles.
Lavage, Sputum, and Other Biological Fluid Samples
Keep all samples on ice until ready for use. The appropriate sample
dilution factor should be optimized by the user.
1. If required, dilute the sample in Bio-Plex sample diluent with BSA
added to a final concentration of 0.5%.
2. Centrifugation at 10,000 x g for 10 min at 4°C may be required to
clarify the sample.