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Paediatric Laboratory Medicine

Barbiturates (U)

Clinical Significance

Barbiturates are a large group of structurally similar sedative-hypnotic drugs which are subject to abuse. Screening assays, such as this, are used to establish the presence or absence of the drug class based on a pre-determined threshold value. Alternative methods must be employed to determine the identity and concentration of any barbiturate from a positive screening result. Barbiturates are grouped in to short-acting and long-acting as follows:

  •  Ultra-short acting: Thiopental 
  • Short acting: Pentobarbital, Secobarbital 
  • Intermediate acting: Amobarbital, Butabarbital, Butalbital 
  • Long acting: Phenobarbital, Barbital 

Sedative-hypnotics are a large group of drugs which cause CNS depression. Most stimulate the activity of Gamma Aminobutyrate (GABA), the principle inhibitory neurotransmitter in the CNS. Similar to the barbiturates, the sedatives can be grouped into short-acting and long-acting as follows:

  • Short acting: Methyprylon
  • Intermediate acting: Glutethimide, Meprobamate, Methaqualone

 Many of the symptoms seen with barbiturate toxicity are also observed with the sedative-hypnotics. These include: lethargy, coma, hypothermia, slurred speech, irritability, respiratory depression and cardiovascular complications.

Test Name

Barbiturates (U)

Alternate Name/ Synonym

Amobarbital, Barbital, Butabarbital, Butalbital, Pentobarbital, Pentobarbital, Secobarbital

Test Code

IBARU

Drug Class

Sedative

Division

Toxicology

Method

Abbott Architect ci4100

External Proficiency Testing

CAP
QMPLS

Turn Around Time

Daily, Stat

Specimen Type

Urine, Miscellaneous Fluid(s)*

Minimum Specimen Requirements

1.0 mL

Storage/Transportation

4°C (transport with a cool pack if possible)

Special Requirements

* For Miscellaneous Fluid(s): phone Toxicology Laboratory (416-813-5906) for availability on specific fluid.

Approval is not required

CPT Codes

80101

Shipping and Contact Information

The Hospital for Sick Children
Rapid Response Laboratory
170 Elizabeth Street, Room 3642
Toronto, ON
M5G 2G3
Canada
Phone: 416-813-7200
Phone: 1-855-381-3212

Therapeutic Range

Not detected

Critical Values

Not Detected < 200 ug/L 
Positive > 201 ug/L