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Report from American Academy of Forensic Sciences

Forensic Drug Abuse Advisor, Vol. 6, Issue 3, March 1994

Workplace drug testing programs can be foiled by adulterating the specimen, and the adulterants can be added inside or outside of the body. Last summer it became apparent that many peole were cheating by adding solutions of concentrated glutaraldehyde (Urinaid) to their voided sample. New data, presented in February at the annual meeting of the American Academy of Forensic Sciences (AAFS), suggests that there is a simpler way to foil urine screening tests: drink lots of water.

Dr. Edward Cone of the Addiction Research Center (ARC) in Baltimore, described the results of a study he had undertaken at the request of Donna Smith, Acting Director of the Department of Transportation's (DOT) Office of Drug Enforcement. Smith was concerned that advertising claims for some herbal teas and "internal cleansing" agents might actually be true. Cone was at first skeptical, but, as he reported at the AAFS meeting, the study was a "sleeper."

Cone set up a series of experiments designed to assess the effect of various measures on "in vivo adulteration." Two of the most popular "teas" were chosen for study; Naturally Klean Herbal Tea" and "Golden Seal" root capsules. Healthy drug-free volunteers with a history of recent drug use were recruited for the study. They were housed in a closed ward for six weeks. The participants were tested under a number of different protocols during that six week period.

At 9:00 AM on the morning of Day One the study subjects smoked a standardized marijuana cigarette (3.58% THC). On Day Three they snorted 40 mg of cocaine. Twenty three hours after each drug was given, they drank one of the following combinations: (1) "Naturally Klean Herbal Tea" in one gallon of water, (2) one gallon of water without any "cleansing agent" (3) one gallon of water with 50 mg of hydrochlorothiadize (a diuretic), (4) four "Golden Seal" capsules and one gallon of water, or (5) twelve ounces of water. Each participant was tested under each protocol and all of the urine was collected.

The urine specimens were then tested by EMIT II assay for cannabinoids at a 50 ng / ml cutoff, and cocaine at a 300 ng / ml cutoff. Specific gravity and creatinine content was measured for each sample, and the two indicators were found to co-vary almost identically. Just drinking 12 ounces of water was enough to cause a significant decrease in both specific gravity and creatinine, but not enough to cause a negative test response. For example, urine cannabinoids levels which were higher than 10,000 ng / ml dropped to the low 100's after drinking 12 ounces of water. After drinking a gallon of water, with or without one of the "cleansing agents" added, it only took an hour for the specific gravity to drop to less than 1.005.

When one gallon of water was drunk, not only did specific gravity fall to very low levels (creatinine<20, and specific gravity <1.003), but the marijuana assay turned negative and stayed that way, even after specific gravity levels had returned to normal! The cocaine tests turned negative for a few hours, but then turned positive again. The same results were observed whether or not tea was used, however, when diuretics were given, the test for both cannabinoids and cocaine turned negative and stayed that way.

Cone concluded that "drug test outcome is highly susceptible to water dilution; and the effects of dilution are reflected concurrently in creatinine and specific gravity measures."

COMMENT: This observation will cause some consternation in the drug testing community, and create more problems than glutaraldehyde and Urinaid adulteration did. It is not that difficult to develop detection strategies for chemicals like glutaraldehyde. That may explain why the practice is already starting to disappear, but setting standards for dilution will be much more difficult. Eventually, it may be necessary to measure drug / creatinine ratios to rule out dilution. Since tests may remain negative even after the specific gravity returns toward normal, it appears that low specific gravities cannot be relied upn to reveal "adulterated" specimens.


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