The Non-Specificity of the Duquenois-Levine Field Test for Marijuana

Abstract

The purpose of this study is to determine the specificity, or lack thereof, of the Duquenois-Levine (D-L) field test kit in the identification of marijuana. Out of the forty-two samples tested, patchouli, spearmint, and eucalyptus tested positive for marijuana using the D-L field test. From these results, it can be concluded that the test is non-specific and can yield false positives. Therefore, it cannot be legitimately used for the prosecution or conviction of an individual for violations of the anti-marijuana laws as it does not provide proof beyond a reasonable doubt of the presence of marijuana. In fact, law enforcement personnel and the test kit manufacturer claim that the D-L field test is a specific, identification test with near perfect accuracy. In court, police officers testify falsely to the identification of marijuana in a seized substance based solely on the D-L test and other non-specific, screening tests leading to convictions. The result is the denial of the Constitutionally-guaranteed right to a fair trial, due process and countless wrongful marijuana convictions.