Test Catalog

Test ID: AMOBS    
Amobarbital, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Monitoring amobarbital therapy

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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)

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Therapeutic concentration: 1.0-5.0 mcg/mL

Toxic concentration: >10.0 mcg/mL

Interpretation Provides information to assist in interpretation of the test results

Amobarbital concentrations above 10 mcg/mL have been associated with toxicity.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The concentration at which toxicity occurs varies and results should be interpreted in light of the clinical situation.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Goodman and Gilman's: The Pharmacological Basis of Therapeutics. 10th edition. New York, McGraw-Hill Book Company, 2001

2. Burtis CA, Ashwood ER, Bruns DE, et al: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Fourth edition. St. Louis, MO, Elsevier Saunders, 2006, pp 1091

3. Disposition of Toxic Drugs and Chemicals in Man. Seventh edition. Edited by RC Baselt. Foster City, CA, Biomedical Publications, 2004, pp 1254

4. Nader R, Horwath AR, Wittwer CT: In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Sixth edition. St. Louis, Elsevier, 2018