Bio-Rad Bio-Plex Pro™ TGF-β Assays - Manual (Page 17)

15
5. Prepare Samples
General guidelines for preparing different sample types are provided here.
For more information, 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 1.5 or 2 ml polypropylene microcentrifuge
tubes. 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
n
Important! before running the assay, samples must be activated and
diluted as described on pages 17–18
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 30–45 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. Activate samples as described below and assay immediately or store
untreated/nonactivated samples in single-use aliquots at –70°C.
Avoid repeated freeze/thaw cycles.