Test Catalog

Test ID: BNZU    
Benzodiazepines Confirmation, Random, Urine

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

Detecting drug use involving benzodiazepines such as alprazolam, chlordiazepoxide, clonazepam, diazepam, midazolam, oxazepam, temazepam, clobazam, flunitrazepam, flurazepam, lorazepam, prazepam, triazolam, and zolpidem

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

Benzodiazepines are any of a group of compounds having a common molecular structure and acting similarly as depressants of the central nervous system. As a class of drugs, benzodiazepines are among the drugs most commonly prescribed in the western hemisphere because of their efficacy, safety, low addiction potential, minimal side effects, and high public demand for sedative and anxiolytic agents.

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.



Cutoff concentrations:

Alprazolam by LC-MS/MS: 10 ng/mL

Alpha-Hydroxyalprazolam by LC-MS/MS: 10 ng/mL

Chlordiazepoxide by LC-MS/MS: 10 ng/mL

Clonazepam by LC-MS/MS: 10 ng/mL

7-Aminoclonazepam by LC-MS/MS: 10 ng/mL

Diazepam by LC-MS/MS: 10 ng/mL

Nordiazepam by LC-MS/MS: 10 ng/mL

Midazolam by LC-MS/MS: 10 ng/mL

Alpha-Hydroxy Midazolam by LC-MS/MS: 10 ng/mL

Oxazepam by LC-MS/MS: 10 ng/mL

Temazepam by LC-MS/MS: 10 ng/mL

Clobazam by LC-MS/MS: 10 ng/mL

N-Desmethylclobazam by LC-MS/MS: 10 ng/mL

Flunitrazepam by LC-MS/MS: 10 ng/mL

7-Aminoflunitrazepam by LC-MS/MS: 10 ng/mL

Flurazepam by LC-MS/MS: 10 ng/mL

2-Hydroxy Ethyl Flurazepam by LC-MS/MS: 10 ng/mL

Lorazepam by LC-MS/MS: 10 ng/mL

Prazepam by LC-MS/MS: 10 ng/mL

Triazolam by LC-MS/MS: 10 ng/mL

Alpha-Hydroxy Triazolam by LC-MS/MS: 10 ng/mL

Zolpidem by LC-MS/MS: 10 ng/mL

Zolpidem Phenyl-4-Carboxylic acid by LC-MS/MS: 10 ng/mL

Interpretation Provides information to assist in interpretation of the test results

Benzodiazepines are extensively metabolized, and the parent compounds are not detected in urine. This test screens for (and confirms) the presence of:



Alpha-hydroxyalprazolam (metabolite of alprazolam)



7-Aminoclonazepam (metabolite of clonazepam)

Diazepam (separate prescribable drug and metabolite of medzazepam)

Nordiazepam (metabolite of clorazepate, halazepam, prazepam, diazepam and medazepam)


Alpha-hydroxy midazolam (metabolite of midazolam)

Oxazepam (separate prescribable drug and metabolite of clorazepate, halazepam, prazepam, medazepam, temazepam, and diazepam)

Temazepam (separate prescribable drug and metabolite of medazepam and diazepam)


N-Desmethylclobazam (metabolite of clobazam)


7-Aminoflunitrazepam (metabolite of flunitrazepam)


2-Hydroxy ethyl flurazepam (metabolite of flurazepam)




Alpha-hydroxy triazolam (metabolite of triazolam)


Zolpidem phenyl-4-carboxylic acid (metabolite of zolpidem)


The clearance half-life of long-acting benzodiazepines is more than 24 hours. It takes 5 to 7 half-lives to clear 98% of a drug dose. Therefore, the presence of a long-acting benzodiazepine greater than the limit of quantification indicates exposure within a 5 to 20-day interval preceding specimen collection. Following a dose of diazepam, the drug and its metabolites appear in the urine within 30 minutes. Peak urine output is reached between 1 and 8 hours. See Mayo Clinic Laboratories Drugs of Abuse Testing Guide at www.mayocliniclabs.com/test-info/drug-book/index.html for additional information including metabolism, clearance (half-life), and approximate detection times.

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

No significant cautionary statements

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

1. Gudin JA, Mogali S, Jones JD, Comer SD: Risks, management, and monitoring of combination of opioid, benzodiazepines, and/or alcohol use. Postgrad Med. 2013;125(4):115-30. doi: 10.3810/pgm.2013.07.2684

2. Manchikanti L, Abdi S, Atluri S, et al: American Society of Interventional Pain Physicians (ASIPP) guidelines for responsible opioid prescribing in chronic non-cancer pain: Part 2-guidance. Pain Physician. 2012;15(3 Supp):S67-116

3. Barkin RL: In: Baselt RC, ed. Disposition of Toxic Drugs and Chemicals in Man. 8th ed. Biomedical Publications; 2008

4. Langman LJ, Bechtel LK, Meier BM, Holstege C: Clinical toxicology. In: Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1328-1333