Butalbital, Serum
Use
This test is useful for monitoring butalbital therapy. Butalbital is a short-acting barbiturate with hypnotic properties, usually combined with other drugs like acetaminophen, salicylate, caffeine, and codeine. It distributes throughout the body, has a volume of distribution of 0.8 L/kg, about 26% is bound to plasma proteins, and has a half-life of 35 to 88 hours. Monitoring its concentration helps in assessing therapeutic levels and avoiding toxicity.
Special Instructions
Specimens collected in serum gel tubes are not acceptable as the drug can absorb on the gel and lead to falsely decreased concentrations. Collect blood samples just before the next scheduled dose and centrifuge within 2 hours, transferring serum to a plastic vial for submission.
Limitations
Butalbital concentrations greater than 10 mcg/mL are associated with toxicity, and gross hemolysis, lipemia, and icterus do not cause rejection. However, samples in serum gel tubes are unacceptable due to potential adsorption issues.
New York Approved
Methodology
Mass Spectrometry (GC-MS)
Biomarkers
LOINC Codes
- 6895-7
- 6895-7
Result Turnaround Time
3-9 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.5 mL
Minimum Volume
0.6 mL
Container
Plastic vial
Collection Instructions
Draw blood immediately before next scheduled dose. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.
Causes for Rejection
Specimens in serum gel tubes are not acceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 28 days |
| Refrigerated | 28 days |
| Frozen | 28 days |