User guide

14
6. Prepare Samples
General guidelines for preparing different sample types are provided
here. For more information, consult publications listed in Bio-Rad bulletin
#5297, available for download at www.bio-rad.com, or contact Bio-Rad
Technical Support.
n
Once thawed, keep samples on ice. Prepare dilutions just prior to the
start of the assay and equilibrate to room temperature before use
n
Prepare sample dilutions in microcentrifuge tubes. Alternatively, if a
multichannel pipet will be used to load the plate, then aliquot the required
volumes into Titertube
®
micro test tubes
n
Do not freeze diluted samples
Serum and Plasma
Note: If using plasma, EDTA or citrate is preferred as an anticoagulant.
Heparin-treated plasma, while compatible with Bio-Plex Pro
™
assays,
may absorb certain soluble proteins of interest. Avoid using hemolyzed
samples as this may lead to false positive results.
1. Draw whole blood into collection tubes containing anticoagulant.
Invert tubes several times to mix.
2. For serum, allow blood to clot at room temperature for 30 to 45 min.
For plasma, proceed directly to the centrifugation steps.
Table 5. Summary of recommended sample diluents and dilution factors.
Sample Type Diluent Add BSA Sample Dilution*
Serum and plasma Sample diluent HB None Fourfold (1:4)
Culture media,
with serum Culture media None User optimized (neat to 1:10)
Culture media,
serum-free Culture media To 0.5% final* User optimized (neat to 1:10)
Lavage, sputum,
other fluids Sample diluent HB To 0.5% final* User optimized (neat to 1:10)
User optimized (at least 1:2 for
Lysate Sample diluent HB To 0.5% final* 200–900 µg/ml final protein)
* At least 0.5% final BSA is recommended to stabilize analytes and reduce adsorption to labware.