Test Code DIL Dilantin
Additional Codes
Epic: LAB31
Specimen Required
Specimen Type: Serum
Collection Container/Type
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 3.5 mL
Collection Instructions:
-
Centrifuge and separate cells after clot formation and within 1 hours of collection.
Specimen Minimum Volume
0.5 mL
Specimen Stability
Room temperature: 2 days
Refrigerated: 8 days
Frozen: 5 months
Clinical Significance
Phenytoin (Dilantin) is one of the most widely prescribed anticonvulsants and is occasionally used as a myocardial antiarrhythmic. In the treatment of epilepsy, phenytoin is indicated for grand mal epilepsy (major motor) and cortical focal seizures and temporal lobe epilepsy.
The main pathway (about 90%) for disposition of phenytoin is by excretion in the urine. It is hydroxylated in the liver and eliminated. The metabolic conversion to HPPH is a saturable process and in many cases small increments in dosage can cause a large increase in phenytoin plasma level. Because of the narrow therapeutic index and the wide inter-individual variability in the rate of phenytoin metabolism and clearance, the determination of blood levels of phenytoin for patients receiving therapy is appropriate.
Reference Range
Theraputic range: 10.0 - 20.0 µg/mL
Rejection Due To
Unlabeled, mislabeled, wrong tube type, QNS, grossly hemolyzed.
Day(s) and Time(s) Performed
Daily
Report Available
Same day
Method Name
Chemiluminescent Microparticle Immunoassay (CMIA)
Aliases
Phenytoin