Test Catalog

Test ID: COKEX    
Cocaine and Metabolite Confirmation, Chain of Custody, Random, Urine

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

Detecting and confirming drug abuse involving cocaine


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.

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

Adulterants testing will be performed on all chain of custody urine samples as per regulatory requirements.

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

Cocaine is a drug of current health concern because of its proliferation among recreational drug abusers.


Freebase and crack increase the potential for major cocaine toxicity. Cocaine use is declining across the nation according to the National Institute of Drug Abuse. 


Increasingly, laboratory results are disputed or there are medical/legal overtones. Therefore, physicians are finding an increased need to confirm positive results before informing or confronting the patients.


Chain of custody is a record of the disposition of a specimen to document 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.


Positives are reported with a quantitative GC-MS result.

Cutoff concentrations:



<150 ng/mL



<50 ng/mL



<50 ng/mL

Interpretation Provides information to assist in interpretation of the test results

Reports will specifically indicate the presence or absence of cocaine and benzoylecgonine.


The presence of cocaine, or its major metabolite, benzoylecgonine, indicates use within the past 4 days.


Cocaine has a 6-hour half-life, so it will be present in urine for 1 day after last use.


Benzoylecgonine has a half-life of 12 hours, so it will be detected in urine up to 72 hours after last use.


There is no correlation between concentration and pharmacologic or toxic effects.

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

Not intended for use in employment-related testing.

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

1. Baselt RC, Cravey RH: Disposition of Toxic Drugs and Chemicals in Man. Third edition. Chicago, Year Book Medical Publishers, 1989

2. Langman LJ, Bechtel L, Holstege CP: Chapter 35. In Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Edited by CA Burtis, ER Ashwood, DE Bruns. WB Saunders Company, 2011, pp 1109-1188