Barbiturates Panel, Blood

Includes

• Amobarbital, Butabarbital, Butalbital, Pentobarbital, Phenobarbital, Secobarbital

Methodology

Gas Chromatography/Mass Spectrometry (GC/MS) 

Assay Category

This test was developed and its performance characteristics have been determined by NMS Labs. It has not been cleared or approved by the US Food and Drug Administration.

Reference Range(s)

Amobarbital: Following a single oral administration of 120 mg, serum concentrations peaked at about 1.8 mcg/mL at 2 hours, and declined slowly thereafter with a half-life of approximately 24 hours. Potentially toxic at plasma concentrations >9 mcg/mL.

Butabarbital: Plasma concentrations of 2-3 mcg/mL produce sedation and plasma concentrations of 25 mcg/mL produce sleep in most patients. Plasma concentrations of >30 mcg/mL may produce coma and plasma concentrations >50 mcg/mL are potentially lethal.

Butalbital: A single oral 100 mg dose resulted in a mean peak blood concentration of 2.1 mcg/mL (range, 1.7-2.6 mcg/mL) at 2 hours, with a decline to 1.5 mcg/mL (range, 1.3-1.7 mcg/mL) by 24 hours. Potentially toxic at plasma concentrations >10 mcg/mL.

Pentobarbital: Peak serum concentrations of 1.2-3.1 mcg/mL were produced 0.5-2.0 hours after a 100 mg oral dose and peak serum concentrations of 3 mcg/mL were produced 6 min. following a 100 mg IV dose. Potentially toxic at blood concentrations >10 mcg/mL.

Phenobarbital: Serum/plasma concentrations of 10-30 mcg/mL are generally considered desireable when given as an anticonvulsant. A blood/plasma ratio of 0.81 has been reported.

Secobarbital: A 3.3 mg/kg oral dose (approx. 230 mg/70 kg) produced a mean peak blood concentration of 2.0 mcg/mL (range, 1.8-2.2 mcg/mL) at 3 hours., diminishing to 1.3 mcg/mL by 20 hours and 0.8 mcg/mL by 40 hours. Potentially toxic at blood concentrations >8 mcg/mL.

LOINC® Codes, Performing Laboratory