1 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.
1 mL heparin (green top) plasma. Centrifuge sample and
separate plasma from cells immediately. Transfer plasma to
a plastic transport tube. Clearly label tube as heparin
plasma. Refrigerate.