The urine test war

Adulteration and dilution of urine specimens to beat the drug test and the laboratory response
Stuart C. Bogema, Ph.D., DABFT Forensic Testing, Inc.

From the beginning of widespread urine drug testing in the 1980s, persons who use drugs have attempted to ‘beat the test’ by altering their normal urine specimen. There are now over thirty million urine drug tests performed each year. The rate of positive tests has steadily declined, but has the rate of altered specimens increased?

Three Methods Used to 'Beat the Test'

There are three means by which persons can alter their urine specimen.

First. They can attempt to substitute an entirely different specimen for their own. Stories of substituting another person's specimen continue, even placing that specimen into the bladder prior to urinating for the drug test. Drug-free urine, even in freeze dried form, has been commercially available for over ten years. Measuring the temperature of the freshly voided urine is the principle means to detect substituted specimens. Observation of the urination is commonly used in criminal justice drug testing programs.

Second. The second commonly used technique to alter the urine specimen is the addition of chemicals to the specimen to interfere with the drug testing procedures. In the 1980s, household products such as table salt, Drano, Visine, bleach, and liquid soaps were used to adulterate the urine. These chemicals could interfere with the immunoassay tests used by drug testing laboratories for the initial drug screen. A commercial market for adulterants has developed with products like nitrite and Urine Luck (pyridinium chlorochromate) available by mail order or over the Internet. The laboratories have countered by utilizing immunoassays less susceptible to adulterants and by testing for the adulterants directly. Laboratories can test for nitrites, glutaraldehyde, acids, bases, and salt. The Substance Abuse and Mental Health Services Administration (SAMHSA), which oversees Federal drug testing for the U.S. Department of Health and Human Services, provided guidance to certified drug testing laboratories on September 28, 1998, regarding reporting of adulterated specimens. It is now more likely that adulterants will be detected by the labs and reported to the Medical Review Officer and the employer.

Third. The third common method to attempt to beat the urine drug test is in vivo dilution of the urine. This means consuming large quantities of beverages in order to dilute the urine prior to urination. The object is to reduce the concentration of drugs and drug metabolites in the urine specimen to below the cutoff level used in the drug tests. Consumption of large quantities of beverages can dilute the urine tenfold or more, thus increasing the possibility that any drug and drug metabolite will be below the drug test cutoff concentration. For example, dilution of a urine specimen that would contain marijuana metabolite at 150 nanograms per milliliter (ng/mL) by tenfold will reduce the marijuana metabolite level to 15 ng/mL. The marijuana metabolite cutoff for a positive initial screen is 50 ng/mL. Therefore, in vivo dilution of the urine can change a positive test to negative. Laboratories use the measurement of creatinine and specific gravity to check for urine dilution. Specific gravity is a measurement of the amount of dissolved solids in the urine. The more water in the urine, the lower the specific gravity. Normal specific gravity ranges from 1.003 to about 1.020. Creatinine is a normal metabolic product that is produced by the body and excreted into the urine in about the same amount each day. Normal levels are in the range of about 40 to 200 milligrams per deciliter (mg/dL) of urine. SAMHSA considers specimens dilute if specific gravity is below 1.003 and creatinine is below 20 mg/dL. SAMHSA considers specimens substituted if the specific gravity is below 1.001 or over 1.020 and the creatinine is less than 5 mg/dl. The laboratories are to report such results to the Medical Review Officer.

On-Site Drug Testing

Over the last several years, rapid drug tests for the SAMHSA five drugs have been developed which allow initial screening of urine specimens in minutes without instrumentation. The Varian, Inc. OnTrak? TesTcup? product requires no physical exposure to the urine specimen while performing the test. A temperature strip is provided so that temperature measurement can be used to check for a freshly voided specimen.

To check for adulteration and dilution of the urine specimen during on-site testing. Varian, Inc. has available the Intect 7Test Strips. This rapid test measures creatinine, nitrites, glutaraldehyde, and pH.

The creatinine portion of the test strip is used to detect a potentially dilute specimen caused by in vivo dilution by consumption of large amounts of beverages or direct addition of water to the specimen. The test strip provides increasing darkness of a purple color as the creatinine concentration increases.

The nitrite test will detect the most commonly used commercial adulterants: Klear, Urine Luck, Whizzies, and others that contain nitrites or pyridinium chlorochromate. A distinctive pink-red color is produced on the test strip with nitrites and a brown color is produced by pyridinium chlorochromate.

The glutaraldehyde test will detect Urinaid and other glutaraldehdye-containing products. A distinctive blue-black color is produced on the test strip.

The pH portion of the test strip detects acids and bases added to the urine. A red color indicates an acid such as THC Free in the specimen and a dark blue color indicates bases such as bleach and liquid drain opener.

The use of the Intect 7 Test Strips can quickly indicate that a urine specimen is potentially abnormal because of an adulterant or dilution. Such a specimen should be sent to a certified laboratory for additional testing for the suspected adulterant or for creatinine and specific gravity testing if the Intect 7 Test Strips shows a low creatinine test.