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. Specimen is stable for two weeks at room temperature, for two weeks refrigerated, and for seven months frozen.