0.5 mL serum from a plain red top tube. Allow sample to clot in an upright position for at least 60 minutes, then centrifuge sample and transfer serum to a plastic transport tube within 2 hours of collection. Clearly label tube as serum from a plain red top tube. Refrigerate.
0.5 mL EDTA plasma. Centrifuge sample and separate plasma from cells within 30 minutes of collection. Transfer plasma to a plastic transport tube. Clearly label tube as EDTA plasma. Refrigerate.
0.5 mL sodium or lithium heparin (green top) plasma. Centrifuge sample and separate plasma from cells within 2 hours of collection. Transfer plasma to a plastic transport tube. Clearly label tube as heparin plasma. Refrigerate.