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.
Submit With Order
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 NameLOINC
0090090Phenytoin Total3968-5
* 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