| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Dilantin
Test CodeDIL
Alias/See Also
Epic: LAB31
D.P.H.
Dilantin (Phenytoin)
Diphenylhydantoin
Phenytoin (Dilantin)
D.P.H.
Dilantin (Phenytoin)
Diphenylhydantoin
Phenytoin (Dilantin)
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL
Minimum Volume
0.5 mL
Instructions
Centrifuge and separate cells after clot formation and within 1 hours of collection
Transport Container
Plastic vial
Specimen Stability
Room temperature: 2 days
Refrigerated: 8 days
Frozen: 5 months
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Unlabeled, mislabeled, wrong tube type, QNS, grossly hemolyzed.
Methodology
Chemiluminescent Microparticle Immunoassay (CMIA)
Setup Schedule
Daily
Report Available
Same day
Reference Range
Theraputic range: 10.0 - 20.0 µg/mL
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.
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.
Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031
Last Updated: March 6, 2023
Last Review: N. Wolford, March 6, 2023