Test Catalog

Test ID: BNZX    
Benzodiazepines Confirmation, Chain of Custody, 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, in urine specimens handled through the chain-of-custody process

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Testing for adulterants will be performed on all chain of custody urine samples per regulatory requirements.

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 most commonly prescribed drugs in the western hemisphere because of their efficacy, safety, low addiction potential, minimal side effects, and high public demand for sedative and anxiolytic agents.


Chain of custody is required whenever the results of testing could be used in a court of law. Its purpose is to protect the rights of the individual contributing the specimen by demonstrating that it was under the control of personnel involved with testing the specimen at all times; this control implies that the opportunity for specimen tampering would be limited. This includes a record of the disposition of a specimen to document the personnel who collected it, who handled it, and who performed the analysis. When a specimen is submitted in this manner, analysis will be performed in such a way that it will withstand regular court scrutiny.

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-minoflunitrazepam (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 https://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