Position Statement: Interpretation of Urine Analysis for Cocaine Metabolites

Introduction, Charles McKay, MD
University of Connecticut School of Medicine
Farmington, CT

Position Statement, American College of Medical Toxicology

Int J Med Toxicol 2000; 3(3): 24


Urine drug screening in the workplace (particularly preplacement screening) has been associated with a decline in absenteeism, workplace theft, and on the job accidents. Administratively, positive results in "for-cause" and post-accident testing have been taken as presumptive evidence of impairment in most jurisdictions.

The American College of Medical Toxicology agrees with the ideal of an unimpaired workforce, but wishes to emphasize that there is no scientifically or medically valid method to equate the mere presence (or quantitation) of a drug or metabolite in a person's urine with clinical impairment due to that drug. The clinical circumstances and condition of the patient must also be evaluated as part of the medical interpretation of the urine drug screen.


The National Institute for Drug Abuse standard for a positive urine for illicit use of cocaine is: 1) a positive screening procedure with a threshold of detection at or above 300 ng/ml with a confirmation of the presence of benzoylecgonine above a threshold at or above 150 ng/ml using gas chromatography/mass spectroscopy and 2) the absence of a history of medically administered cocaine anesthetic. A positive test by these criteria may be interpreted as establishing the introduction of cocaine into the body by any route at some time prior to the collection of the urine specimen. The most probable time frame is within three days but occasionally a positive test may be present weeks after the most recent use of high doses of cocaine.

Equating a positive urine test to the presence of impairment at particular time prior to the urine collection is without scientific merit.

Nothing herein should be construed to condone the use of cocaine nor to suggest that cocaine cannot induce impairment.


  1. Code of Federal Regulations (1998). 49CFR40.29 (e) (1) and (f) (1).
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  10. Shults T (1999). Drug Testing and Worker’s Compensation Litigation. Medical Review Officer Handbook 7th Edition. 291-294.


Int J Med Toxicol 2000; 3(3): 24

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