Bio-Rad Bio-Plex Pro™ Human Th17 Cytokine Assays - Manual (Page 16)

14
Sample Preparation
Serum and 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.
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 HB (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.
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, lysate,
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* 50 to 500 ug/ml final protein)
*At least 0.5% final BSA is recommended to stabilize analytes and reduce absorption to labware.