Drug testing is an approach used to test individuals for the presence of psychoactive drugs. Testing generally uses some form of biological specimen, generally urine, hair or saliva.

Generally speaking, drug tests can detect use of illicit drugs within several hours or days of use. Many factors may influence whether a particular drug test will successfully detect any given individual’s recent drug use. These include how recently someone has taken a drug and what percentage of detectable metabolites are still present in their body at the time they are tested. A negative result typically gives accurate information about that specific instance of testing but cannot be interpreted as meaning that “drugs are never used” by that person or “drugs were previously used.”

A federal law enacted in 1988 provides companies with the right to require their employees to be drug tested. The law states that all safety-sensitive transportation workers who are in “high risk” jobs (e.g., bus drivers, airplane pilots, train engineers or subway operators) must be subject to random drug and alcohol testing for drugs including marijuana, alcohol and other drugs. This includes pre-employment drug testing as well as random urine tests while employed in these critical transportation jobs.

The Federal government also requires compliance with strict guidelines in the collection of specimens used in the mandatory drug testing of federal employees in DOT-regulated industries; however, not all employers who test their employees for drugs are required to follow these regulations. Because they were developed specifically for this purpose, many experts recommend using DOT guidelines for all other drug tests.

Under the federal regulations, all DOT drug testing must be conducted by or under the supervision of a Medical Review Officer (MRO). Also, it is now typical to use hair samples as opposed to urine samples in most employment drug testing programs because hair testing can detect drug use within several months of single-time ingestion, while urine testing cannot generally do so unless there has been chronic abuse over many months. The following types of specimens are accepted by Substance Abuse & Mental Health Services Administration (SAMHSA) for federally mandated post-accident and reasonable suspicion drug testing:

Collection Procedures

All urine specimens must be collected using FDA-approved chain-of-custody procedures. This means that the urine sample must be collected in a way that maintains the privacy of the donor and establishes an accurate record of who provided the sample, when it was provided and where it was kept between collection and testing.

The following procedure is typical:

the donor will present to a designated person, usually the MRO or a person under direct supervision of the MRO;

this designated person will check identification documents against a roster of eligible donors;

urine samples are required to be collected as close as possible to the time they are due for drug testing;  proximity to timing requirements ensures that individuals cannot substitute samples from other people who have tested negative for drugs;

upon completion, labeled specimen would then be closed with tamper seals and given to the designated person who then hands it over to an individual authorized by the MRO;

this authorized person would provide security for all documentation of chain-of-custody procedures. Depending on the size of the company, this might be done within a Human Resources or safety department or at a contracted third party facility.

Federally mandated drug testing requires that only laboratories with SAMHSA approval may test specimens. According to DOT regulations, urine tests must be conducted using one of five approved immunoassay technologies: EMIT (or Abuscreen), Syva EMIT II, Roche Diagnostics’ CEDIA (or TDx) and Siemens MEA. Gas chromatography/mass spectrometry (GC/MS) may be used to confirm a positive amphetamine result. Hair samples for federally mandated drug testing must be taken with special precautions in order to prevent adulteration or substitution of specimens. This means that most companies will use a third-party professional collection site, which is usually a medical laboratory, a company specializing in forensic toxicology, an occupational health clinic or a physician’s office under direct supervision of an MRO.

In addition, federally mandated postaccident drug testing requires that all urine specimens meet the following requirements:

the donor provides at least 45 ml of urine;

collection containers used for specimen collection must have been purchased from the original sample collector and not from another;  specimen appears clear and colorless;

specimen temperature is within the range of 15-30 °C (60-86 °F);

the donor’s urine concentration must be at least 100 mg/dL. If it is below this concentration, confirmation via GC/MS may be required. After 180 ml has been collected or three hours have passed since the specimen was started, whichever comes first, the donor must not eat any food until after he or she has provided a second specimen. This requirement exists because many foods contain natural diuretics that affect urine tests by diluting the concentrations of some drugs in urine samples. Any company collecting specimens for federally mandated drug testing should establish procedures for handling substitution and adulterated specimens to prevent false negative results.

Federally mandated postaccident drug testing requires that all urine specimens meet the following requirements:

the donor provides at least 45 ml of urine;

collection containers used for specimen collection must have been purchased from the original sample collector and not from another;  specimen appears clear and colorless;

specimen temperature is within the range of 15-30 °C (60-86 °F);

the donor’s urine concentration must be at least 100 mg/dL. If it is below this concentration, confirmation via GC/MS may be required. After 180 ml has been collected or three hours have passed since the specimen was started, whichever comes first, the donor must not eat any food until after he or she has provided a second specimen. This requirement exists because many foods contain natural diuretics that affect urine tests by diluting the concentrations of some drugs in urine samples. Any company collecting specimens for federally mandated drug testing should establish procedures for handling substitution and adulterated specimens to prevent false negative results.

Federally mandated postaccident drug testing requires that all urine specimens meet the following requirements:

the donor provides at least 45 ml of urine;

collection containers used for specimen collection must have been purchased from the original sample collector and not from another;  specimen appears clear and colorless;

specimen temperature is within the range of 15-30 °C (60-86 °F);

the donor’s urine concentration must be at least 100 mg/dL. If it is below this concentration, confirmation via GC/MS may be required. After 180 ml has been collected or three hours have passed since the specimen was started, whichever comes first, the donor must not eat any food until after he or she has provided a second specimen. This requirement exists because many foods contain natural diuretics that affect urine tests by diluting the concentrations of some drugs in urine samples. Any company collecting specimens for federally mandated drug testing should establish procedures for handling substitution and adulterated specimens to prevent false negative results.