Handling dilution, substitution and adulteration in drug testin

Drug testing in the workplace has many challenges. Finding a qualified laboratory, collection site and review officer are among the challenges to companies doing or looking to set up a drug and alcohol-testing program.

What drugs to test for and what samples -- urine, blood, hair, saliva or breath -- are most appropriate for a company's testing program?

One challenge that has been present since the early days of drug and alcohol testing is that of specimen integrity.

Donors have tried many different ways to eliminate the drugs from their system faster, mask the drugs that they have taken, substitute their specimen with another (drug-free) specimen at the time of collection, or alter their specimen by ingesting or adding chemicals that cause the drugs in the specimen to not be detectable. Collection sites and drug-testing laboratories have worked to identify specimens that have been altered or develop identification methods that are not affected by these attempts to invalidate the drug-testing procedure.

Offered here are some of the processes that are used to defeat the drug-testing process and how these attempts can be overcome by collection sites and laboratories.

What kinds of things are tried?

* Dilution of specimens.

Urine specimens may be diluted either by adding water to them at the time of collection or by drinking large quantities of water shortly before the drug screen collection occurs. In both cases, the concentration of drugs in the collected specimen may fall below the cut-off necessary to call a specimen positive. Cut-offs are somewhat arbitrary concentrations set either by federal or state regulation to be the minimum concentration of drug necessary to call a specimen positive.

* Substitutions of specimens.

Some donors make an attempt to substitute other liquids for the urine specimen at the time of collection. Various substances have been used for this and include colored water, yellow-colored soft drinks such as Mountain Dew, purchased artificial urine or drug-free urine.

* Adulteration of specimens.

Some donors may add chemical substances to their urine specimens at the time of collection in the hope of rendering the subsequent testing inoperable. Substances used for this purpose have included acid (swimming pool treatment chemical), bases (Draino) and oxidizing agents (bleach).

What can be done to deter or detect these attempts?

* Collection sites.

Good collection procedures can deter attempts to dilute, substitute or adulterate urine specimens. These procedures include lack of water in the collection site, bluing in the toilets, and the use of temperature strips on the collection vessel.

Urine collected from a donor will have a temperature of between 90- 100 degrees Fahrenheit. Temperatures below this range would generally indicate that the urine specimen has been carried into the collection site and put into the collection bottle.

The collection site should perform an immediate recollection with observation. A temperature above the range would generally indicate an attempt to artificially heat a specimen carried into the collection site.

* Testing laboratory.

Certified laboratories are able to test for many of the commonly used adulterants and the normal urine constituents need to detect dilution or substitution.

Creatinine is a normal component of human urine. Creatinine is produced in a rather constant amount by skeletal muscle and excreted into the urine. Urine lacking creatinine or having an extremely low concentration would indicate dilution or substitution.

Specific gravity is a measurement of the amount of dissolved substances in urine. Extremely low specific gravity results would also indicate dilution or adulteration.

pH is an indication of the acidity or basicity of a urine specimen. High pH results would indicate the addition of a base like Draino to the specimen and low pH results would indicate the addition of an acid. Both excessive high and low pH results would indicate an attempt to adulterate the specimen and invalidate the testing process.

The list of adulterants that have been tried or are being used is long. The trade names for some of these include -- Whizzes, SuperClean13, Urine Luck, Stealth and UrinAid. Laboratories are generally able to detect several of these adulterants. These adulterants may contain bleach, soap, gluteraldehyde, nitrites and other chemical agents. When these are detected they indicate an attempt to adulterate and invalidate the testing process.

What can be done with donors who dilute, substitutes or adulterates their specimens?

* Federal guidelines.

Under federal drug testing guideline specimens found to be diluted may be recollected with same-sex observation. This is not mandatory and studies have shown that only about 10 percent of diluted specimens actually contain any detectable drug. Donors presenting specimens that are substituted or adulterated are treated as refusal to test and may be terminated.

* Oklahoma guidelines.

The state regulations do not speak to diluted, substituted or adulterated specimens. It is left up to company policy as to how to handle these situations. It is generally recommended that the federal guidelines be followed for donors falling under the state testing guidelines.

Attempts to cheat drug testing by intentional dilution, substitution or adulteration represent a serious challenge to companies, collection sites, drug-testing laboratories and federal and state regulators. Maintaining good collection practices, utilizing high-quality, certified laboratories and maintaining vigilance about what things are being tried are critical to the success of workplace drug-testing programs.

Michael W. Fowler is director of toxicology at the St. Anthony Hospital Toxicology Laboratory.

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