Phenytoin (Dilantin)

Message

Phenytoin specimens should be drawn just before the next dose for trough . If toxicity is suspected, specimens may be drawn at any time.

Test Code

PTN

CPT Codes
80185

Preferred Specimen

GREEN Lithium Heparin Plasma

Minimum Volume

0.25 mL

Other Acceptable Specimens

SST Serum Separator, Red No Gel

Instructions

Separate from cells within 4 hour of collection

Transport Container

GREEN Lithium Heparin

Transport Temperature

Room Temperature

Specimen Stability

Room Temperature: 8 hours; Refrigerated: 7 days

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

Not separated from cells within 4 hours of collection, Gross hemolysis

Methodology
Vitros 7600/3400

Reference Range

Therapeutic Range: 10-20 ug/mL; Critical Value: >30 ug/mL

Clinical Significance

Phenytoin is a widely prescribed anticonvulsant drug used in the treatment of generalized and partial seizures. Phenytoin measurements are used to monitor patient compliance and therapy and to diagnose potential overdose.

Performed By
RFGH Laboratory

Performing Laboratory
RFGH Laboratory

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.