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US DOL DRUG-FREE WORKPLACE ADVISOR

How is drug testing conducted and how accurate is it?

Generally, most private employers have a fair amount of latitude in implementing drug testing as they see fit for their organization, unless they are subject to certain Federal regulations, such as the U.S. Department of Transportation’s (DOT) drug-testing rules for employees in safety-sensitive positions.  However, Federal agencies conducting drug testing must follow standardized procedures established by the Substance Abuse and Mental Health Services Administration (SAMHSA), part of the U.S. Department of Health and Human Services (DHHS).

While private employers are not required to follow these guidelines, doing so can help them stay on safe legal ground.  Court decisions have supported following these guidelines, and as a result, many employers choose to follow them.  These Mandatory Guidelines for Federal Workplace Drug Testing (also called SAMHSA’s guidelines) include having a Medical Review Officer (MRO) evaluate tests.  They also identify the five substances tested for in Federal drug-testing programs and require the use of drug labs certified by SAMHSA.

The most common method of drug testing, urinalysis, can be done at the workplace (at a health unit, for example), a doctor’s office or any other site selected by the employer.  An employee or applicant provides a sample to be tested.  Usually precautions are taken, such as putting blue dye in the toilet and turning off the water supply, to prevent adulteration or substitution of specimens so that collection can be completed in privacy without any direct visual observation by another person. 

Under SAMHSA’s guidelines, once a sample is provided, it is sent to a certified laboratory.  The accuracy of drug tests done by certified laboratories is very high, but this certification applies only to the five substances tested for in Federal drug-testing programs and alcohol.

Below are certain procedures required by SAMHSA’s guidelines to ensure accuracy and validity of the testing process:

  • Chain of Custody: A chain-of-custody form is used to document the handling and storage of a sample from the time it is collected until the time it is disposed.  It links an individual to his or her sample and is written proof of all that happens to the specimen while at the collection site and the laboratory.

  • Initial Screen: The first analysis done on a sample is called an initial screen.  This one test alone is not always accurate or reliable; there is a possibility of a false positive.  Thus, in the event that the initial screen is positive, a second confirmatory test should be done.

  • Confirmation Test:  A second, confirmation test (by gas chromatography/mass spectrometry or GC/MS) is highly accurate and provides specificity to help rule out any false positives (mistakes) from the initial screen.  For a test result to be reported as positive, the initial screen and confirmation test results must agree. 

  • Split Sample:  A split sample is created when an initial urine sample is split into two.  One sample is used for the initial screen and, if positive, the second sample is used for the confirmation test.  If there is a positive result, the individual being tested may request the confirmation test be done at a different laboratory.  DOT's alcohol and drug-testing regulations require all tests be performed using a “split sample” collection process.

In the event that the initial screen and confirmation test are both positive,  MRO, a licensed medical doctor who has special training in the area of substance abuse, then reviews the results, makes sure the chain-of-custody procedures were followed, and contacts the individual to make sure there are no medical or other reasons for the result.  It is only at this point that the MRO may report a positive test result to the employer.  Certain medications can sometimes cause a positive result.  If this is the case, and a doctor prescribed the medicine and the employee used it in the proper amount, the test is reported as negative.

What drugs do tests detect?

Testing conducted according to SAMHSA’s guidelines checks for five illicit drugs plus, in some cases, alcohol (ethanol, ethyl alcohol, booze).  These five illicit drugs are:

  • Amphetamines (meth, speed, crank, ecstasy)

  • THC (cannabinoids, marijuana, hash)

  • Cocaine (coke, crack)

  • Opiates (heroin, opium, codeine, morphine)

  • Phencyclidine (PCP, angel dust) 

However, most private employers are not limited in the number of substances they can test for, and may include drugs that individuals legitimately and/or therapeutically take based on a physician’s prescription. Although most private employers can test for any combination of drugs, there are commonly selected “panels.”

The typical 8-Panel Test includes the above-mentioned substances plus:

  • Barbiturates (phenobarbital, butalbital, secobarbital, downers)

  • Benzodiazepines (tranquilizers like Valium, Librium, Xanax)

  • Methaqualone (Quaaludes)

The typical 10-Panel Test includes the 8-Panel Test plus:

  • Methadone (often used to treat heroin addiction)

  • Propoxyphene (Darvon compounds)

Testing can also be done for:

  • Hallucinogens (LSD, mushrooms, mescaline, peyote)

  • Inhalants (paint, glue, hairspray)

  • Anabolic steroids (synthesized, muscle-building hormones)

  • Hydrocodone (prescription medication known as Lortab, Vicodin, Oxycodone)

  • MDMA ( commonly known as Ecstasy)

How long are drugs in one’s system?

Drugs have certain “detection windows”—the amount of time after ingestion during which evidence of their use can be detected by a drug test.  Though it might not be wise to publicize detection windows and invite employees who may use drugs to push their limits, when implementing drug testing, it is important to understand them.  For instance, alcohol is absorbed and eliminated more quickly than other drugs.  This is why post-accident testing procedures often require testing for alcohol to occur within two hours.  Other drugs are eliminated from the system at different rates and thus detectable for different periods of time, often long after the drug's effect has worn off.  The following are estimates of the length of time that certain drugs are detectable:

  • Alcohol – 1 oz. for 1.5 hours 

  • Amphetamines – 48 hours 

  • Barbiturates – 2-10 days 

  • Benzodiazepines – 2-3 weeks 

  • Cocaine – 2-10 days 

  • Heroin Metabolite – less than 1 day 

  • Morphine – 2-3 days 

  • LSD – 8 hours 

  • Marijuana – casual use, 3-4 days; chronic use, several weeks

  • Methamphetamine – 2-3 days 

  • Methadone – 2-3 days 

  • Phencyclidine (PCP) – 1 week

 

 

 

Marijuana
It is important to note that marijuana remains a drug listed in Schedule I of the Controlled Substances Act. It remains unacceptable for any safety - sensitive employee subject to drug testing under the Department of Transportation's drug testing regulations to use marijuana.

 

http://www.dot.gov/odapc/dot-recreational-marijuana-notice

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