Test Code Billings Clinic: 4037 Dilantin® (Phenytoin), Plasma
Performing Laboratory
Billings Clinic Laboratory: Chemistry
Useful For
Monitoring Dilantin therapy
Methodology
Particle Enhanced Turbidimetric Inhibition Immunoassay (PETINIA)
Specimen Requirements
Submit only 1 of the following specimens:
Serum or plasma should be physically separated from cells as soon as possible with a maximum limit of two hours from the time of collection.
Plasma
- Draw blood in a green-top (lithium heparin) tube(s) 5 to 6 hours after last dose.
- Spin down and send 1.0 mL of heparinized plasma frozen.
- Date and time of last dose and date and time of draw are required on request form
Serum
- Draw blood in a plain, red-top tube(s) or a serum gel tube(s) 5 to 6 hours after last dose.
- Spin down and send 1.0 mL of serum frozen
- Date and time of last dose and date and time of draw are required on request form for processing.
Storage/Stability
Specimen Type | Temperature | Time |
Plasma | Refrigerated | 2 days |
Frozen (preferred) | 5 months | |
Ambient | 24 hours |
Reject Due To
- Gross hemolysis
Reference Values
- Therapeutic concentration: 10-20 µg/mL
- Call-back toxic concentration value: >20 µg/mL
Day(s) Test Set Up
Daily
Test Classification and CPT Coding
80185 - Phenytoin; total
LOINC Code Information
Reporting Name | LOINC Code |
Dilantin | 3968-5 |