10067 Phenytoin (Dilantin), Total

Specimen Type Specimen Stability Reference Range
Serum Refrigerated - 10 Day(s)/Frozen - 30 Day(s)/Ambient - 5 Day(s) 10 - 20 mg/L

Specimen Requirements

Specimen Type: Serum
Container: 1 Red Top Tube
Temperature: Refrigerated
Preferred Vol: 1.5 mL
Min Vol: 1.0 mL




Monday - Saturday

Turn-Around Time



Collect as a trough just before next dose. For patients receiving fosphenytoin therapy, collect as a trough at least 2 hours after IV infusion or at least 4 hours after intramuscular (IM) injection. Serum separator tubes are not acceptable.

Clinical Utility

Phenytoin is an anticonvulsant drug, used for the treatment of epilepsy, particularly grand mal epilepsy, cortical focal seizures and temporal lobe epilepsy. Effective dosage is essential in regulating the effects of seizures. Toxicity of phenytoin usually affects the central nervous system. It is essential that phenytoin levels be monitored to adjust dosage requirements in achieving optimal therapeutic effects while avoiding both subtherapeutic and toxic drug levels.

CPT Codes

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