For serum, collect blood from fasting subjects in a red top tube (for example BD #366431). Immediately after blood collection, place the tubes upright in a rack and allow blood to clot at room temperature for a minimum of 2 hours.
For plasma, collect blood from fasting subjects in a tube containing either lithium heparin (green top, for example BD #367884) or EDTA (purple top, for example BD #367861). Invert tubes several times immediately after collection and place horizontally on a platform rocker at moderate speed for 2 hours at room temperature.
To harvest serum or plasma, centrifuge the tubes at 1500xg for 15 minutes and collect supernatant. Transfer 0.25 ml into a clean 0.5 to 2.0 ml cryogenic vial and store frozen until shipment.
For urine, collect first morning urine at mid stream and transfer 0.25 ml into a clean 0.5 to 2.0 ml cryogenic vial and store frozen until shipment.
To minimize sample loss during liquid handling, we prefer externally threaded cryogenic vials (for example USA Scientific Safety-Seal Screw Cap Tubes, cat# 1405-9700 or for example Nalgene System 100 cryoware). If desired, contact us for advice regarding selection of cryogenic vials for your project.