Phenytoin

Test Code

PTN

Alias/See Also

Dilantin

Preferred Specimen

1 mL serum collected in a red-top tube (no gel)

Patient Preparation
Collect as a trough just prior to next dose. For patients receiving fosphenytoin therapy, collect as a trough at least 2 hours after IV infusion or at least 4 hours after IM injection.

Minimum Volume

0.5 mL

Other Acceptable Specimens

Heparinized plasma (no gel)

Instructions

Include last dose information with order

Transport Container

Transport tube

Transport Temperature

Ambient

Specimen Stability

Ambeint: 2 days
Refrigerated: 7 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Serum separator tube, plasma separator tube

Methodology
Immunoassay (IA)

Setup Schedule

24/7

Report Available

Same day

Reference Range

10.0-20.0 ug/mL

Clinical Significance

Phenytoin is an anticonvulsant hydantoin used for the treatment of generalized tonic-clonic (grand mal) and complex partial seizures. Phenytoin is also used for prophylaxis in neurosurgical procedures. Phenytoin levels are monitored to assure adequate therapeutic levels are achieved and to avoid toxicity.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.