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Test Code BTBAS Butabarbital, Serum


Specimen 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 the next scheduled dose.

2. Within 2 hours of collection, centrifuge and aliquot serum into a plastic vial.


Secondary ID

622885

Useful For

Monitoring of butabarbital therapy

Method Name

Gas Chromatography Mass Spectrometry (GC-MS)

Reporting Name

Butabarbital, S

Specimen Type

Serum Red

Specimen Minimum Volume

0.6 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Red Refrigerated (preferred) 28 days
  Ambient  28 days
  Frozen  28 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Clinical Information

Butabarbital is a short to intermediate acting barbiturate derivative that is US Food and Drug Administration-approved for use in insomnia, in preoperative sedation, and as a hypnotic agent. Butabarbital is extensively metabolized and eliminated primarily by renal excretion. The elimination half-life ranges from 34 to 100 hours.

Reference Values

Therapeutic range:

2.0-3.0 mcg/mL Hypnosis

25 mcg/mL Sedation/Sleep

>30 mcg/mL Coma

Toxic concentration: >50 mcg/mL

 

Cutoff concentrations by gas chromatography mass spectrometry:

Butabarbital: 0.5 ng/mL

Interpretation

Butabarbital concentrations between 2.0 and 3.0 mcg/mL have been used for hypnosis/sedation with concentrations up to 25 mcg/mL used for sleep. Toxic concentrations have been reported as greater than 50 mcg/mL.

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.

Clinical Reference

1. Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:chap 43

2. Baselt RC. Disposition of Toxic Drugs and Chemical in Man. 12th ed. Biomedical Publications; 2020

3. Milone MC, Shaw LM. Therapeutic drugs and their management. In: Rifai N, Chiu RWK, Young I, Burnham CAD, Wittwer CT, eds. Tietz Textbook of Laboratory Medicine. 7th ed. Elsevier; 2023:420-453

4. Mihic SJ, Mayfield J. Hypnotics and sedatives. In: Brunton LL, Knollmann BC, eds. Goodman and Gilman's The Pharmacological Basis of Therapeutics. 14th ed. McGraw-Hill Education; 2023

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 the analysis performed by gas chromatography mass spectrometry using selected ion monitoring. The assay utilizes deuterated barbiturates as internal standards.(Unpublished Mayo method)

Day(s) Performed

Thursday

Report Available

3 to 9 days

Specimen Retention Time

2 weeks

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80299

LOINC Code Information

Test ID Test Order Name Order LOINC Value
BTBAS Butabarbital, S 16236-2

 

Result ID Test Result Name Result LOINC Value
622885 Butabarbital, S 16236-2