Ordering Recommendation

Optimize drug therapy and monitor patient adherence. Can be ordered when fosphenytoin is administered.

Mnemonic
DIL
Methodology

Enzyme Immunoassay

Performed

Sun-Sat

Reported

Within 24 hours

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Plain red.

Specimen Preparation

Allow serum specimen to clot completely at room temperature to ensure complete clot formation has taken place prior to centrifugation. Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.2 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Specimens collected in separator tubes, sodium fluoride, potassium oxalate, EDTA tubes. Hemolyzed specimens.

Remarks
Stability

After separation from cells: Ambient: 8 hours; Refrigerated: 4 days; Frozen: 1 month

Reference Interval

0-2 months: 6.0-14.0 µg/mL
  Toxic: 14.1 µg/mL  or greater 
3 months and older: 10.0-20.0 µg/mL
  Toxic: 30.1 µg/mL or greater

Interpretive Data

The therapeutic range for phenytoin applies to non-uremic patients. In critically ill uremic patients who are receiving fosphenytoin, the value reported may be higher than the patient's actual serum concentration due to interfering substances.

Compliance Category

FDA

Note
Hotline History
N/A
CPT Codes

80185

Components
Component Test Code* Component Chart Name LOINC
0090090 Phenytoin Total 3968-5
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Dilantin
  • Phenytoin, Total, Serum
  • Total phenytoin
Phenytoin