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Drug Testing

What Kinds of Tests Are Available?

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What Kinds of Tests Are Available?

Urinalysis, the most common drug testing method, has been studied exhaustively and used extensively, has undergone rigorous challenge in the courts, and has proved to be accurate and reliable. As a result, urinalysis currently is the only technique approved for drug testing in the Federal workforce. Some employers, however, have already begun using other types of drug tests—on hair, sweat, and oral fluids.

Following are summaries of the most commonly used tests:


Results of a urine test show the presence or absence of specific drugs or drug metabolites in the urine. Metabolites are drug residues that remain in the system for some time after the effects of the drug have worn off. A positive urine test does not necessarily mean the subject was under the influence of drugs at the time of the test. Rather, it detects and measures use of a particular drug within the previous few days.


Analysis of hair may provide a much longer “testing window” for the presence of drugs and drug metabolites, giving a more complete drug-use history that goes back as far as 90 days. Like urine testing, hair testing does not provide evidence of current impairment, only past use of a specific drug. Hair testing cannot be used to detect alcohol.

Sweat Patch

Another type of drug test consists of a skin patch that measures drugs and drug metabolites in perspiration. The patch, which looks like a large adhesive bandage, is applied to the skin and worn for some length of time. A gas-permeable membrane on the patch protects the tested area from dirt and other contaminants. The sweat patch is sometimes used in the criminal justice system to monitor drug use by parolees and probationers, but so far it has not been widely used in workplaces or schools.

Oral Fluids

Traces of drugs, drug metabolites, and alcohol can be detected in oral fluids, the generic term for saliva and other material collected from the mouth. Oral fluids are easy to collect—a swab of the inner cheek is the most common way. They are harder to adulterate or substitute, and collection is less invasive than with urine or hair testing. Because drugs and drug metabolites do not remain in oral fluids as long as they do in urine, this method shows more promise in determining current use and impairment.

Breath Alcohol

Unlike urine tests, breath-alcohol tests do detect and measure current alcohol levels. The subject blows into a breath-alcohol test device, and the results are given as a number, known as the Blood Alcohol Concentration, which shows the level of alcohol in the blood at the time the test was taken. According to the U.S. Department of Transportation regulations, an alcohol level of 0.04 is high enough to stop someone from performing a safety- sensitive task for that day.

What Does Each Test Measure?

Drug tests are used to determine whether a person has used alcohol or illegal drugs. Some tests show recent use only, while others indicate use over a longer period. Each type of test has different applications and is used to detect a specific drug or group of drugs. The Federal Drug-Free Workplace program, which serves as a model for accuracy and quality assurance in drug testing, relies on a urine test designed to detect the use of marijuana, opiates, cocaine, amphetamines, and phencyclidine (PCP). Urine tests can also be used to detect alcohol, LSD, and cotenine, the major metabolite of nicotine.

Who Does the Testing?

Laboratories all over the country perform drug tests, but not all of them produce consistently accurate and reliable results. Many employers and schools choose labs from among those certified by the Substance Abuse and Mental Health Services Administration (SAMHSA) to perform urine testing for Federal agencies. A list of SAMHSA-certified labs is available on the Internet at http://workplace.samhsa.gov/DrugTesting/Level_1_Pages/CertifiedLabs.html.

How Much Do Drug Tests Cost?

The price of drug testing varies according to the type of test and the drugs involved, but generally the cost is between $10 and $30 per test, with hair testing somewhat higher. The price for onsite alcohol tests usually ranges from $1 to $10 per test.

Source: What You Need To Know About Drug Testing in Schools, published by the Office of National Drug Control Policy