Belgrade, Serbia: Urine samples adulterated by various household cleaning products will yield false negative results for cannabinoids and are undetectable by laboratory screening, according to findings published in the journal Archives of Industrial Hygiene and Toxicology.
A team of Serbian researchers 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.
Urine reagent strips failed to identify the presence of three adulterants: vinegar, lemon juice, and citric acid, However, 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.
Authors concluded: “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.”
Full text of the study, “Effect of urine adulterants on commercial drug abuse screening test strip results,” appears in Archives of Industrial Hygiene and Toxicology. Additional information on drug screens and cannabis is online.