One 7.5 mL serum separator tube (SST). Also acceptable: One 4.5 mL light green plasma separator tube (PST).
Handling:
Allow to clot, centrifuge and separate serum or plasma from cells within 2 hours. Refrigerate. Freeze if specimen cannot be assayed within 48 hours. Allow no more than one freeze/thaw cycle.
Stability:
8 hours ambient, 48 hours refrigerated, or frozen on month at -20o C.