Guilty or not guilty? - False positive results of common medicines in drug tests: review and practical guide

Abstract

Drug-abuse detection tests are becoming increasingly commonplace in patient care today and provide a rapid and effective method for identifying illicit substances. Occasionally, they may yield a positive result, indicating the presence of a substance, even though the individual has not consumed the suspected drug what sometimes can significantly impact both medical and legal decisions. The study outlines the substances that can lead to false-positive drug test results for amphetamines, cannabinoids, and benzodiazepines. The study's findings have revealed pivotal insights for patients receiving chronic treatment and their primary care physicians. Notably, amphetamine assays appear to be most prone to cross-reactivity with other substances. The beta-blocker group of medications, confirmed by various studies to interfere with amphetamine assays, could pose a substantial challenge in drug screening given its widespread use. Efavirenz also warrants mention, as it frequently triggers positive results for both benzodiazepine and cannabinoid assays among its users. This research helps highlight new areas for further investigation and aims to guide clinicians in their daily practice, especially when interpreting questionable positive drug-abuse test results. This comprehensive review serves as a valuable resource for clinicians to navigate false-positive scenarios effectively and maintain the highest standard of patient care.

Keywords: amphetamine; benzodiazepines; cannabinoids; cross-reactivity; false positive; urine drug test.