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HelpTest Code AMOBS Amobarbital, Serum
Reporting Name
Amobarbital, SUseful For
Monitoring amobarbital therapy
Method Name
Gas Chromatography Mass Spectrometry (GC-MS)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
Serum RedSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube: Red top (Serum gel/SST are not acceptable)
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL
Collection Instructions:
1. Draw blood immediately before next scheduled dose.
2. Centrifuge and aliquot serum into a plastic vial within 2 hours of collection.
Specimen Minimum Volume
0.6 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum Red | Refrigerated (preferred) | 14 days | |
| Ambient | 14 days | ||
| Frozen | 14 days |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | OK |
Reference Values
Therapeutic concentration: 1.0-5.0 mcg/mL
Toxic concentration: >10.0 mcg/mL
Day(s) Performed
Thursday
CPT Code Information
80299
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| AMOBS | Amobarbital, S | 3338-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8325 | Amobarbital, S | 3338-1 |
Clinical Information
Amobarbital is an intermediate-acting barbiturate with hypnotic properties used in short-term treatment of insomnia and to reduce anxiety and provide sedation preoperatively.(1,2)
Amobarbital is administered by intravenous infusion or intramuscular injection. The duration of its hypnotic effect is about 6 to 8 hours. The drug distributes throughout the body, with a volume of distribution of 0.9 to 1.4 L/kg, and about 59% of a dose is bound to plasma proteins. Metabolism takes place in the liver primarily via hepatic microsomal enzymes. Its half-life is about 15 to 40 hours (mean: 25 hours). Excretion occurs mainly in the urine.(2,3)
Interpretation
Amobarbital concentrations above 10 mcg/mL have been associated with toxicity.
Cautions
The concentration at which toxicity occurs varies, and results should be interpreted in light of the clinical situation.
Specimens collected in serum gel tubes are not acceptable because the drug can absorb on the gel and lead to falsely decreased concentrations.
Method Description
Barbiturates are extracted from serum using solid-phase extraction techniques. The serum is buffered and eluted with organic solvent. The organic phase is dried, reconstituted, and analysis performed by gas chromatography mass spectrometry using selected ion monitoring. The assay utilizes deuterated barbiturates as internal standards.(Unpublished Mayo method)