Benzodiazepines (BENZ)

CPT Code: 80101

Specimen:  Urine

Volume: 30 mL

Container:  Use plastic urine drug bottle and evidence tape or tamper-evident container for forensic specimen. Collection kits are available by request from the laboratory.

Collection:  Urine specimens should be collected in clean, unbreakable, and leak proof containers.  Freshly voided urine specimens should be used.

Fresh urine specimens do not require any special pretreatment.  No additives or preservatives are required.  Boric acid should not be used as a preservative. 

Specimens may be encountered that display turbidity.  It is recommended that such specimens be centrifuged before analysis.

Specimens should be within the pH range of 5-8.  Specimens with a pH outside this range should be adjusted to this range by the addition of 1N HCl or 1N NaOH before analysis.

Specimens should be at a temperature of 20-25 ⁰C before analysis.


Stability:  If not analyzed immediately, specimens should be stored refrigerated for less than 24 hours.  Specimens should be frozen if storage longer than 24 hours is required.

Cutoff:  200 ng/mL

Note: This method provides only a preliminary analytical test result.  A more specific alternate chemical method must be used in order to obtain a confirmed analytical result.  Gas chromatography/mass spectrometry (GC/MS) is the preferred confirmatory method.  Other chemical confirmation methods are available.  Clinical consideration and professional judgment should be applied to any drug of abuse test result, particularly when preliminary positive results are used.

Use:  Measurements obtained with BENZ method are used in the diagnosis and treatment of benzodiazepines use or overdose.

Information:  Benzodiazepines are sedative-hypnotic drugs that are structurally similar and include widely used drugs such as chlordiazepoxide, diazepam, and oxazepam.  The different benzodiazepines are absorbed at different rates, and the timing of their psychoactive effects varies with the absorption rate.  Benzodiazepines are usually taken orally and are metabolized in the liver.  Some benzodiazepine metabolites are pharmacologically active.  Benzodiazepines potentiate the effect of other central nervous system depressants, such as ethyl alcohol.

Methodology:  EMIT®