Phenobarbital, Total/Unbound/Bound, S/P
Also known as: PHENOBAR
Use
This test is used to optimize drug therapy and monitor patient adherence by measuring the levels of phenobarbital. It assesses the total, unbound (free), and bound concentrations of phenobarbital in serum or plasma, aiding in the management of anticonvulsant therapy and ensuring appropriate therapeutic levels are maintained.
Special Instructions
The test is not performed at ARUP; separate specimens must be submitted when multiple tests are ordered. It is important to separate the serum or plasma from cells as soon as possible or within 2 hours of collection. This test requires a minimum of 0.9 mL of serum or plasma for analysis.
Limitations
The test utilizes High Performance Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS), which is a selective and sensitive method for measuring phenobarbital. However, it has not been cleared or approved by the US Food and Drug Administration. The test cannot be performed using separator tubes, which are considered unacceptable conditions. Bound phenobarbital is calculated by subtracting the unbound fraction from the total concentration, and errors in these measurements may affect the accuracy of the bound phenobarbital calculation.
New York Approved
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 3948-7
- 3951-1
Result Turnaround Time
8-11 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
0.9 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Separate from cells ASAP or within 2 hours of collection.
Causes for Rejection
Separator tubes.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 3 months |
| Refrigerated | 3 months |
| Frozen | 18 months |