Phenytoin
Performing Lab(s)
Memorial-Belleville only
Specimen Requirement (s)
Specimen Type: Plasma
Container/Tube: mint green LiHep Tube (preffered)
Specimen Volume: 1 mL
Specimen Minimum Volume: 0.5 mL plasma
Collection Instructions:
- IV: 2-4 hours following completion of infusion loading dose.
- Oral:
- Peak - 3-9 hours following administration of drug.
- Trough - Not more than 30 minutes before next dose.
Lab instructions: NA
Day(s)/Shift(s) Test Set Up and Turnaround Time
Sunday through Saturday
Hours: 24 hours
Turnaround Time:
STAT: 60 minutes
Routine: less than 8 hours from receipt.
Transport and Stability
Transport temperature: Ambient to lab
Reference Values
Phenytoin
Age |
Reference Values |
Critical High |
0 – 3 months |
10 – 20 mcg/mL |
≥ 14 mcg/mL |
>3 months |
10 – 20 mcg/mL |
≥ 29 mcg/mL |
Note: Therapeutic or toxic effects of anticonvulsant drugs may occur at different concentrations in different patients, and the correlation between dose and clinical effect must be evaluated individually.
CPT/LOINC Codes
80185