Due to a nationwide shortage of the filter used to prepare Free Phenytoin samples for testing, Free Phenytoin testing is not currently available in the lab at Parkview Regional Medical Center. If Free Phenytoin testing (EPIC Test Code LAB32) is needed, continue to order utilizing your normal process. Orders for in house testing will automatically be forwarded to Quest Diagnostics for testing. Specimen requirements remain the same. Time to result availability is expected to increase by approximately 3 days. Availability of Total Phenytoin testing remains unchanged. The shortage is currently expected to remain in effect until the end of 2024. Notification will be sent when testing is available again inhouse. Questions about this temporary test change should be referred to Dr. Ling Hui, Chemistry Technical Director, at 266-1365 or Ann Vick, Laboratory Chemistry Specialist, at 266-1587.
* This volume does not allow for repeat testing
Should be drawn 2 - 4 hours after IV Dose, or just prior to next oral dose
Quest instructions:
Collect as a trough just prior to next dose. For patients receiving fosphenytoin therapy, collect as peak (at least 2 hours after IV infusion or at least 4 hours after IM injection).
Centrifuge and separate from cells within 24 hours of collection
Serum Separator Tube (SST)
Plasma Separator Tube (PST)
Plasma
1 - 2 mcg/ml
Temporary Quest:
1.0-2.0 mg/L
Same Day/1 to 2 days
01420189
80186