Bio-Rad Human Metabolic and Hormone Assays - Manual (Page 16)

14
Protease Inhibitors
In general, these biomarkers are detectable in serum or plasma without
using protease inhibitors. Users may choose to add protease inhibitors as
a precautionary measure if samples will not be frozen immediately after
collection. Alternatively, blood sample collection tubes containing inhibitors
may be obtained from Becton-Dickinson, www.bd.com.
Note: Protease inhibitors are not recommended for use with serum
samples. Compatibility of a given inhibitor cocktail with the assays must
be validated by the end user.
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. Prepare sample dilutions in 0.5 or 1.0 ml polypropylene tubes as
required for the assay.
6. Dilution scenarios provided below are sufficient to run each sample in
duplicate.