Human serum or plasma
Collect blood into either a plain vacutainer (red top) for serum or a pre-chilled vacutainer containing heparin (green top) for plasma. If collecting serum, allow the blood to clot at RT for 30 minutes, then centrifuge at 1500 x g for 15 minutes. To prepare plasma samples, centrifuge the EDTA blood immediately for 15 minutes at 1500 x g in a refrigerated centrifuge set at 4o C. Since MMP-9 is released upon platelet activation, an additional centrifugation step of the plasma (10,000 x g for 10 min at 2 – 8o C) is recommended for complete platelet removal. Transfer either the serum or the platelet-free plasma to a labeled 12 x 75 mm polypropylene tube. Store at -80 until time of assay.
N.B. EDTA and Citrate are not recommended anticoagulants for use in this assay due to their chelating properties.
The R&D Systems enzyme immunoassay (EIA) requires only 10 µl of serum/plasma since a 100-fold dilution of serum and a 40-fold dilution of plasma is necessary prior to microplating.
Suggested blood sample size: 1 ml
