PHENYTOIN

Test Code

DIL

Alias/See Also

Dilantin

CPT Codes
80185

Preferred Specimen

1 Red tube

Patient Preparation
Draw immediately prior to next dose.

Minimum Volume

0.5 mL

Other Acceptable Specimens

1 Lavender tube (EDTA) or 1 Green tube (Lithium Heparin) or 1 Gold tube (stable no more than 24 hours from time of collection if refrigerated).

Instructions

Centrifuge for complete separation of plasma or serum from red cells. Aliquot (transfer) serum or plasma into transfer tube. Refrigerate until tested.

Transport Container

Standard transport tube.

Transport Temperature

Refrigerate

Specimen Stability

2-8°C up to 7 days; Frozen up to 3 months

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

Hemolysis interferes

Methodology

EIA

Setup Schedule

M, T, W, Th, F, Sa, Sun

Report Available

Within 24 hours of receipt at the performing laboratory.

Reference Range

10 - 20 µg/mL

Clinical Significance

Used in the diagnosis and treatment of phenytoin overdose and in monitoring levels of phenytoin to ensure proper dosing.

Performed By
Alverno Laboratories

Performing Laboratory
Alverno Central Lab
NCHB1 (Chemistry, Beckman AU)

Last Updated: January 17, 2024

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.