One 5 mL red top tube preferred. Also acceptable: One 4 mL green top tube (heparin) or one 4 mL lavender top tube (EDTA). Serum separator tube (SST) or gel barrier tubes may decrease phenytoin level from 16-22% in 24 hours and are not recommended.
Handling:
Must be centrifuged within 2 hours, the serum or plasma separated from cells and poured into a plastic vial for transport. Refrigerate. Freeze if specimen cannot be assayed within 48 hours. Allow no more than one freeze/thaw cycle. Note date and time of last dose.
Stability:
48 hours refrigerated.
Standard Volume:
0.5 mL serum or plasma.
Minimum Volume:
150 µL serum or plasma.
Transport:
Refrigerated, or frozen on dry ice.
Comments:
Refer to the drug manufacturer’s package insert or the Physicians’ Desk Reference for proper dosage and for phenytoin measurement sampling times.
Rejection Criteria:
Specimen frozen and thawed more than once; refrigerated specimen received in laboratory more than 48 hours after collection.
Print View Attached Docs: