Item Value
Test name Phenytoin, Free
Available Stat? No
Turn around times Run 5x per week. Turnaround 3-5 days
Performed by Quest
Normal range
Therapeutic 1.0-2.0 µg/mL
Potentially toxic > 3.0 µg/mL
Container type Red top (Gold top NOT acceptable)
Amount to Collect 5 mL blood
Collection Instructions Time to steady state: 3-4 days

Collect samples 30 minutes before AM dose.

Draw at least 4 hours post-IV dose and 6-9 hours post-PO dose

Collect in Red top tube only. Avoid hemolysis.

Order total phenytoin separately if desired. Indicate time of collection on requiisition.
Sample type Serum

If you have additional questions regarding this test, please call: 415-353-1667