Specimen Requirements

Specimen must arrive within 24 hours of draw.

Submit only 1 of the following specimens:

Plasma

Container/Tube: Green-top (heparin) plasma gel tube

Specimen Volume: 0.5 mL of heparinized plasma

Transport Temperature: Refrigerate

Collection Instructions: Draw specimen representing the trough level just before next dose. Specimens from patients receiving fosphenytoin should be drawn at least 2 hours following intravenous (IV) administration and 4 hours following intramuscular (IM) administration per the recommendations of the manufacturer. The change in the phenytoin concentration is dependent on the amount of time that has elapsed since the administration of fosphenytoin.

Note: 1. Indicate plasma.

2. Label specimen appropriately (plasma).

Serum

Container/Tube: Gold-top serum gel tube

Specimen Volume: 0.5 mL of serum

Transport Temperature: Refrigerate

Collection Instructions: Draw specimen representing the trough level just before next dose. Specimens from patients receiving fosphenytoin should be drawn at least 2 hours following IV administration and 4 hours following IM administration per the recommendations of the manufacturer. The change in the phenytoin concentration is dependent on the amount of time that has elapsed since the administration of fosphenytoin.
Note: 1. Indicate serum.

2. Label specimen appropriately (serum).