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New study indicates false positives possible for hair drug tests

new study from Scientific Reports may have an effect on what kind of drug tests employers choose to use when screening potential employees for marijuana. The study, entitled “Finding cannabinoids in hair does not prove cannabis consumption,” shows that three cannabinoids — tetrahydrocannabinol (THC), 11-nor-9-carboxy-THC (THC-COOH) and tetrahydrocannabinolic acid A (THCA-A) — can be found in hair samples even if the samples came from a person who had never used the drug. “Our studies show that all three cannabinoids can be present in hair of non-consuming individuals because of transfer through cannabis consumers, via their hands, their sebum/sweat, or cannabis smoke,” wrote the authors in the abstract. In fact, according to the study, the THC-COOH cannabinoid (which is created in the body and can be transferred to other individuals via sweat/sebum on the hands or other parts of the body) can remain on hair follicles for up to 11 weeks after contamination, which could end up resulting in false-positive drug tests. THC itself can be found in marijuana smoke, which can lead to risk of “external contamination.” Because marijuana is still illegal on a federal level, despite it becoming legalized in some states, it is still legal for many employers to conduct drug tests for the drug, and even take adverse action against individuals who test positive. At this time, urine and blood tests are much less likely to turn up “false positives” for marijuana usage, and employers may consider utilizing these drug-testing methods when conducting pre-employment or on-the-job screening. Contact Mind Your Business to keep up to date on your rights as an employer when dealing with the murky waters of drug-testing laws.]]>

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