Urine Testing for Marijuana Use

Abstract

<h3>To the Editor.—</h3> Testing urine for cannabinoids, the drug components of marijuana, has become common because relatively simple testing methods are now available. The presence of cannabinoids in urine indicates marijuana use, and a great deal of weight is often placed on positive findings. It is implied that performance is impaired while driving, flying, or operating hazardous machinery and that proficiency and learning ability are reduced. Persons whose urine yields positive test results are accused of possessing and using the drug. They are punished by convictions, fines, imprisonment, and loss of privileges, jobs, reputations, and careers. For this much weight to be placed on the results of an assay, there should be no question concerning the validity of the results; the drug identification must be positive and beyond any reasonable doubt. If safety is an issue, it should be shown that the person was adversely affected or that all people