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Test Code DILN Phenytoin (Dilantin) Level

Important Note

Draw 12 hours post oral dose or just prior to next dose. Draw 2 to 4 hours post IV loading dose. Falsely elevated results may be caused by renal deficiency.

Additional Codes

EPIC LAB4161

Synonyms

  • Diphenylhydantoin

Clinical Significance

Phenytoin (Dilantin) is indicated for the treatment of grand mal and cortical focal seizures and temporal lobe epilepsy. Phenytoin therapy is monitored for suspected inadequate dose or toxicity.

 

Source: Beckman Coulter Unicel, PHY IFU. REF #469188 5/11/15

Methodology

Particle enhanced turbidimetric inhibition immunoassay (Beckman Coulter UniCel DxC 660i)

Sample Type

Preferred Sample Type
Light green top - Plasma

 

Acceptable Sample Types
Dark green top - Plasma
Yellow top - Serum
Red top - Serum

Centrifuge: Yes

Specimen Minimum Volume

0.3 mL

Specimen Stability

Temperature Time
Ambient air (18-25°C) 8 hours
Refrigerated (2-8°C) (store) 48 hours
Frozen (-15 to -20°C) 1 month

Separate plasma or serum from cells within 2 hours.

Reference Ranges

Therapeutic Range
10 - 20 ug/mL

 

Critical Value
>20 ug/mL

 

Technical Range
2.5 - 40.0 ug/mL

Rejection Criteria

Hemolysis N/A
Icterus N/A
Lipemia N/A

 

Availability

Performed STAT
24/7 Yes

 

Performing Laboratory

MultiCare Yakima Memorial Hospital Laboratory

Lab Department

Chemistry

CPT Code

80185

LOINC

3968-5 Phenytoin [Mass/Vol]