Urine Drug Tests Are Effectively Adulterated by Household Cleaning Products, Finds Study

According to a new study published in the journal Archives of Industrial Hygiene and Toxicology, urine samples adulterated by various household cleaning products will yield false negative results for cannabinoids and are undetectable by laboratory screening. The study, titled Effect of urine adulterants on commercial drug abuse screening test strip results, was first reported on by NORML.

For the study, researchers from Serbia adulterated drug-positive urine samples with minute amounts of household cleaning products. “The addition of several additives – including vinegar, lemon juice, bleach, and benzalkonium chloride (an antiseptic agent used in hand sanitizer) – yielded false positive results for cannabinoids on immunochromatographic strips tests.” The use of Visine eye drops did not alter the test results.



During the study urine reagent strips failed to identify the presence of three adulterants which were vinegar, lemon juice, and citric acid, Follow up pH testing did eventually reveal inconsistencies in the samples adulterated with lemon juice and citric acid. “By contrast, samples adulterated with vinegar consistently avoided laboratory detection.”

The study concludes by stating: “To the best of our knowledge, until this study of ours, no one has reported research data about household chemicals interfering with urine drug test results. … In terms of tampering, our study shows that UDST [urine drug screening tests] for cannabinoids are susceptible to urine adulterants, as [they] yielded six false negative results. … The most potent adulterant that barely changed the physiological properties of urine specimens and therefore escaped adulteration detection was vinegar. … Our findings raise concern about this issue of preventing urine tampering and call for better control at sampling, privacy concerns notwithstanding, and better sample validity tests.”

The study’s full abstract states:


Immunochromatographic strips for urine drug screening tests (UDSTs) are common and very suitable for drug abuse monitoring, but are also highly susceptible to adulterants kept in the household, which can significantly alter test results. The aim of this study was to see how some of these common adulterants affect UDST results in practice and whether they can be detected by sample validity tests with pH and URIT 11G test strips. To this end we added household chemicals (acids, alkalis, oxidizing agents, surfactants, and miscellaneous substances) to urine samples positive for amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), tetrahydrocannabinol, heroin, cocaine, or benzodiazepines (diazepam or alprazolam) and tested them with one-component immunochromatographic UDST strips. The UDST for cocaine resisted adulteration the most, while the cannabis test produced the most false negative results. The most potent adulterant that barely changed the physiological properties of urine specimens and therefore escaped adulteration detection was vinegar. Besides lemon juice, it produced the most false negative test results. In conclusion, some urine adulterants, such as vinegar, could pass urine specimen validity test and remain undetected by laboratory testing. Our findings raise concern about this issue of preventing urine tampering and call for better control at sampling, privacy concerns notwithstanding, and better sample validity tests.

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