One 7.5 mL serum separator tube (SST). Also acceptable: One 4 mL green top tube (heparin), one 4.5 mL plasma separator tube (PST), or one 4 mL lavender top tube (EDTA).
Centrifuge serum or plasma separator tube within 2 hours of collection and transport in original tube. Specimen drawn in green (heparin) or lavender top tube must be centrifuged within 2 hours of collection and the plasma separated into a plastic vial for transport. Refrigerate. Note last dose date and time. If specimen cannot be assayed within 48 hours, freeze.
0.5 mL serum or plasma.
150 uL serum or plasma.
Refrigerated if received in laboratory within 48 hours of collection, or frozen on dry ice.
Routine monitoring: Draw just before next dose. Overdose monitoring: Draw at 1 hour and 4 hours after ingestion.
Specimen that has been collected in potassium oxalate/sodium fluoride or sodium citrate anticoagulants; refrigerated specimen received in laboratory more than 48 hours after collection.