Therapeutic drug management
Serum or plasma
Red-top tube or green-top (heparin) tube. Gel-barrier tubes are not recommended.
Trough levels are most reproducible.
Serum or plasma should be separated from cells within two hours of venipuncture. Submit serum or plasma in a plastic transport tube.
Submission/transport (<3 days): Room temperature. For storage beyond three days, specimen should be refrigerated or frozen.