Ordering Recommendation
Optimize drug therapy and monitor patient adherence. Can be ordered when fosphenytoin is administered.
Mnemonic
Methodology
Enzyme Immunoassay
Performed
Sun-Sat
Reported
Within 24 hours
New York DOH Approval Status
Specimen Required
Plain red.
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)
Refrigerated.
Specimens collected in separator tubes, sodium fluoride, potassium oxalate, EDTA tubes. Hemolyzed specimens.
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.
FDA
Note
Hotline History
CPT Codes
80185
Components
Component Test Code* | Component Chart Name | LOINC |
---|---|---|
0090090 | Phenytoin Total | 3968-5 |
Aliases
- Dilantin
- Phenytoin, Total, Serum
- Total phenytoin