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The Duquenois reagent is used in the Rapid Modified Duquenois–Levine test, an established screening test for the presence of marijuana. The test was initially developed in the 1930s by Pierre Duquénois, and was adopted in the 1950s by the United Nations as the preferred test for cannabis, and originally claimed to be specific to cannabis. After several modifications, it became known as the Duquenois–Levine test. However, in the 1960s and 70s various studies showed that the test was not specific to cannabis. In 1973 the Supreme Court of Wisconsin ruled the D–L test insufficient evidence for demonstrating that a substance was cannabis, specifically noting that the D–L tests used "are not exclusive or specific for marijuana." The test is one of several forms of modern cannabis drug testing. ==Specificity== In the 1960s and 70s various studies showed that the D–L test was not specific to cannabis, although some flawed studies claimed to show the opposite. A 1969 UK government scientist〔M.J. de Faubert Maunder, ("Two Simple Colour Tests for Cannabis" ), UNODC Bulletin on Naarcotics, Issue 4 – 005, (1969), 37-42〕 reported twenty-five plant substances giving a D–L test result very similar to that of cannabis and warned that the D–L test "should never be relied upon as the only positive evidence."Another 1969 study〔R.F. Turk, H. Dharir, & R.B. Forney, A Simple Chemical Method to Identify Marijuana, 14, Journal of Forensic Sciences, (1969), 389〕 found false positives from "a variety of vegetable extracts".
The study most cited in favour of the specificity of the D–L test is Thornton and Nakamura (1972). The authors themselves reported that the D–L test gave false positives, but declared the D–L test confirmatory when combined with the presence of cystolithic hairs, which marijuana plants possess. However, many plant species have such hairs, and the study only confirmed that 82 of them did not give D–L test false positives. A 2000 study by the US NIST〔 examined 12 chemical spot tests, and concluded that all the tests examined "may indicate a specific drug or class of drugs is in the sample, but the tests are not always specific for a single drug or ()", and noted that "mace, nutmeg and tea reacted with the modified Duquenois–Levine ()".〔John Kelly (2008), (False Positives Equal False Justice ), p4〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Duquenois–Levine reagent」の詳細全文を読む スポンサード リンク
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