Phenytoin
0090090
 
Ordering Recommendation
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. For plasma specimens, ensure centrifugation is adequate to remove platelets. 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.
Note
CPT Code(s)
80185
Components
Component Test Code*Component Chart Name
0090090Phenytoin Total
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, contact interface support at interface.support@aruplab.com.
Cross References
  • Dilantin
  • Phenytoin, Total, Serum
  • Total phenytoin