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Paediatric Laboratory Medicine

Benzodiazepines (U)

Clinical Significance

Benzodiazepines are a large group of structurally similar sedative-hypnotic drugs which are subject to abuse. Therapeutic serum concentrations and toxic levels are different for each benzodiazepine. 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 benzodiazepine from a positive screening result. Originally introduced in the 1960s, benzodiazepines are used for a variety of situations including: seizure control, anxiety, alcohol withdrawal, insomnia, muscle relaxants and pre-anesthetic agents. Toxicity symptoms include: dizziness, confusion, drowsiness, unresponsiveness, anxiety, slurred speech, coma, altered mental status, amnesia and respiratory depression.

Test Name

Benzodiazepines (U)

Test Code


Drug Class






External Proficiency Testing


Turn Around Time

Daily, Stat

Specimen Type

Urine, Miscellaneous Fluid(s)*

Minimum Specimen Requirements

1.0 mL


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


Shipping and Contact Information

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

Therapeutic Range

Not detected

Critical Values

Not Detected < 50 ug/L
Positive > 51 ug/L